Molecular Self-Assembly in Substrate Processing

ABSTRACT

Methods for sealing a porous dielectric are presented including: receiving a substrate, the substrate including the porous dielectric; exposing the substrate to an organosilane, where the organosilane includes a hydrolysable group for facilitating attachment with the porous dielectric, and where the organosilane does not include an alkyl group; and forming a layer as a result of the exposing to seal the porous dielectric. In some embodiments, methods are presented where the organosilane includes: alkynyl groups, aryl groups, fluoroalkyl groups, heteroaryl groups, alcohol groups, thiol groups, amine groups, thiocarbamate groups, ester groups, ether groups, sulfide groups, and nitrile groups. In some embodiments, method further include: removing contamination from the porous dielectric and a conductive region of the substrate prior to the exposing; and removing contamination from the conductive region after the forming.

CROSS REFERENCE TO RELATED APPLICATIONS

The present invention is related to the following applications, all ofwhich are incorporated herein by reference for all purposes:

This application is a continuation application of U.S. patentapplication Ser. No. 13/045,298, filed on Mar. 10, 2011, which is adivisional application of U.S. patent application Ser. No. 11/932,033,which is a continuation of U.S. patent application Ser. No. 11/284,572,which application claims the benefit of U.S. Patent Application60/630,485, filed Nov. 22, 2004, which is related to U.S. patentapplication Ser. Nos. 11/132,817 and 11/132,841, both filed May 18,2005, and U.S. patent application Ser. No. 11/231,047, filed Sep. 19,2005.

TECHNICAL FIELD

The disclosure herein relates generally to processing a substrate and,more particularly, to substrate processing using molecular self-assemblyto form one or more layers between a dielectric and electricallyconductive materials.

BACKGROUND

The manufacturing of various electronic devices (including but notlimited to for example, microprocessors, storage devices, graphicprocessors, analog to digital converters, digital to analog converters,signal processors, image processors, etc.) now requires thecost-effective production of very small structures and features, e.g.,structures and features having a characteristic dimension at themicrometer or nanometer size scale. This manufacturing includes theformation of electrically conductive material(s) (e.g., aluminum,copper, etc.) and electrically insulating dielectric material(s) (e.g.,silicon dioxide, silicon nitride, etc.) on or as part of a substrate.Moreover, the electrically conductive material(s) are typicallyseparated by regions of dielectric material(s) so as to defineelectrical elements (e.g., transistors, capacitors, etc.) andinterconnections between such electrical elements.

Many electronic devices include multiple layers of electrical elementsand/or interconnections (e.g., interconnect layer(s)). Each interconnectlayer comprises conductive material(s) separated by dielectricmaterial(s). As an example, a first layer of dielectric material isformed on an electrically conductive material (first conductive layer).A second layer of dielectric material is formed on the first layer ofdielectric material. Trenches (e.g. lines) are formed in the secondlayer of dielectric material, and vias (e.g., holes) are then formed inthe first layer of dielectric material. Electrically conductive materialis subsequently formed in the trenches and vias so as to electricallyconnect the now electrically conductive trenches (second conductivelayer) to the electrically conductive material (first conductive layer)through the now electrically conductive vias.

Copper is commonly used as the electrically conductive material inelectronic devices. Copper can be used to fill trenches and/or vias (orother, similar features) of an electronic device. A description of amethod for forming a copper interconnection between electrical elementsformed in or on a substrate (e.g. semiconductor) follows. The formationof a copper interconnection etches a structure (e.g., trenches and/orvias) in a dielectric material (e.g., silicon dioxide). A barrier layer(e.g., tantalum and/or tantalum nitride) is formed on the dielectricmaterial. The barrier layer prevents diffusion of copper into thedielectric material. The barrier layer should also adhere well to thedielectric material and to the copper subsequently formed on the barrierlayer. A seed layer of copper is formed on the barrier layer. Copper isthen formed to fill the trench or via using a bulk formation process(e.g., an electrochemical deposition process).

The formation of copper interconnects includes two copper formationsteps and because copper formed using the bulk copper formation processdoes not nucleate and/or adhere well on the formed barrier layer. Thisnecessitates the formation of a copper seed layer, using a process otherthan a bulk formation process, on which the bulk copper does nucleateand/or adhere, for example, by providing an electrochemically reactivelayer for subsequent electrochemical deposition of copper. Additionally,the two copper formation steps and are used because the copper seedlayer formation step by itself (e.g., physical vapor deposition,sputtering) does not adequately fill the vias and trenches because ofnon-conformal step coverage produced by the physical vapor depositionprocess (e.g., breadloafing or excessive overhang of deposited materialat the top of a trench, via or other feature).

In an alternative process or method for forming a copper interconnectionbetween electrical elements formed in or on a substrate (e.g.semiconductor), the seed layer can be a material (e.g. ruthenium,platinum, etc.) other than copper on which copper formed using the bulkcopper formation process does nucleate and/or adhere well (e.g.,electrochemical deposition). In another variant, the barrier layerformed can be a material like ruthenium on which copper can besatisfactorily formed (e.g. with good nucleation and/or adhesion) duringthe bulk formation so as to eliminate the need for the copper seedlayer.

Physical vapor deposition (PVD) has been used to form a barrier layer inmethods such as those described above with reference to FIGS. 1 and 2.However, as feature sizes shrink, the barrier layer (which has higherresistivity as compared to copper) consumes an increasing percentage ofthe total interconnect (e.g. via and line) volume for a fixed barrierlayer thickness which limits the overall conductivity of theinterconnect structure(s). It therefore has become necessary to form ordeposit ultra-thin barrier materials (e.g., on the order of less than 50angstroms thick) to maximize copper volume within the interconnectstructure(s). Overhang or breadloafing has increasingly become a problemwhen using PVD to form an ultra-thin barrier layer. One approach toreduce this problem has been the use of ionized PVD (and can be inconjunction with resputtering) whereby sputtered atoms of the barrierlayer material are ionized and made to move more directionally towardthe bottom regions of features which reduces overhang. Resputteringenables some localized shaping and/or redistribution of depositedmaterial.

One limitation of ionized PVD is that the achievable step coverage (orconformality of the deposited material with respect to the substratetopography) is lower than desired, e.g., can be less than 20% for 5:1aspect ratio (height to width), 0.1 μm via structures, especially at thevia mid to lower sidewall regions. Also, the trench and via bottom andsidewall surfaces can be roughened as a result of the ionized PVDprocess; this can produce an increase in electron scattering effectswith an undesirable increase in line and via resistance. Additionally,PVD processes are line-of-sight which may not produce process resultsacross an entire substrate that are as uniform as desired because thelocation of a feature on the substrate and characteristics of thefeature (e.g., aspect ratio, orientation) can affect the step coverageachieved for that feature.

Recently, atomic layer deposition (ALD) has been used in barrier layerformation. The use of ALD to form a barrier layer can mitigate problemsencountered in the use of PVD. For example, ALD enables uniform,conformal deposition of ultra-thin barrier layers that have becomenecessary to accommodate the increasingly small features and structuresbeing formed on semiconductor substrates. Relative to PVD, ALD can alsoprovide improved repeatability of process results, as well as moreuniform process results across an entire substrate. However, thereactants (e.g., precursor, reactants, and carrier gases, etc.) used inan ALD process are undesirably susceptible to diffusion into thedielectric material (particularly the porous low-k dielectric materialsthat are increasingly being used). In addition, ALD barrier layers oftensuffer from poorer adhesion properties (e.g., copper adhesion to ALD TaNis worse than to PVD Ta).

A combination of PVD and ALD has also been used. However, while this canalleviate some of the problems described above, others persist. The mostsignificant ongoing problem is the incompatibility of ALD barriermaterials with porous dielectric materials due to the diffusion of theALD reactants into the pores of porous dielectric materials.

Molecular self-assembly is a technique that can be used to produce verysmall structures and features, e.g., structures and features having acharacteristic dimension at or below the nanometer size scales.Molecular self-assembly can be used to produce a variety of materialformations, such as molecular monolayers (often referred to asself-assembled monolayers, or SAMs), molecular multilayers andnanostructures (e.g., nanotubes, Buckey balls, nanowires). For example,a SAM has been used as a barrier layer (replacing the deposited barrierlayer, as described above) that inhibits diffusion of copper into adielectric material. However, this SAM inhibits copper diffusion intoSiO₂ or fluorinated SiO₂, both of which are non-porous dielectricmaterials.

Porous dielectric materials provide additional challenges to inhibitingdiffusion because the pores of porous dielectric materials provideanother diffusion pathway for foreign material (e.g., barrier layermaterial, copper) into the dielectric material. SAMs have been proposedfor use as bulk diffusion barrier layers, especially for use with densedielectric materials such as silicon dioxide. There is a need for theprevention of diffusion of foreign material through the exposed pores ofporous dielectrics.

INCORPORATION BY REFERENCE

Each publication, patent, and/or patent application mentioned in thisspecification is herein incorporated by reference in its entirety to thesame extent as if each individual publication and/or patent applicationwas specifically and individually indicated to be incorporated byreference.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings and in whichlike reference numerals refer to similar elements and in which:

FIG. 1 is a flow diagram for use of a MSAL with a barrier layer inproducing an interconnection between electrical elements formed in or ona semiconductor substrate, under an embodiment.

FIG. 2A is a cross-sectional view of the substrate that includestrenches and vias formed in a dielectric material of the substrate.

FIG. 2B is a cross-sectional view of the substrate including a MSALformed on the dielectric material, under an embodiment.

FIG. 2C is a cross-sectional view of the substrate including a barrierlayer formed on the MSAL, under an embodiment.

FIG. 2D is a cross-sectional view of the substrate includingelectrically conductive material formed in the trenches and vias overthe barrier layer, under an embodiment.

FIG. 3 is a flow diagram for use of a MSAL in producing aninterconnection between electrical elements formed in or on asemiconductor substrate, under an embodiment.

FIG. 4A is a cross-sectional view of a substrate in which a trenches andvias are formed in a dielectric material of the substrate.

FIG. 4B is a cross-sectional view of the substrate with a molecularlyself-assembled layer formed on the dielectric material, under anembodiment.

FIG. 4C is a cross-sectional view of the substrate includingelectrically conductive material formed in the trenches and vias overthe molecularly self-assembled layer, under an embodiment.

FIG. 5 is a flow diagram for forming a MSAL as a diffusion barrierand/or adhesion layer between electrically conductive and dielectricmaterials, under an embodiment.

FIG. 6A shows an organosilane that includes three hydrolyzable groups,under an embodiment.

FIG. 6B shows a MSAL formation process using an organosilane with threehydrolyzable groups, under an embodiment.

FIG. 7 is an example of MSAL formation using an organosilane with onehydrolyzable group, under an embodiment.

FIG. 8 is a flow diagram for sealing porous low-k dielectrics, under anembodiment.

FIG. 9 shows examples that the effective extent of material removed fromthe bottom(s) of structures is size-dependent and aspectratio-dependent.

FIG. 10A is a flow diagram for interconnect integration using molecularself-assembly, under an embodiment.

FIGS. 10B-10F show an example of interconnect integration usingmolecular self-assembly, under an embodiment.

FIG. 11A is a flow diagram for interconnect integration using molecularself-assembly, under an alternative embodiment.

FIGS. 11B-11G show an example of interconnect integration usingmolecular self-assembly, under an alternative embodiment.

FIG. 12 is a flow diagram for seed layer formation using bifunctionalmolecular self-assembly, under an embodiment.

FIG. 13 is a flow diagram for seed layer formation using monofunctionalmolecular self-assembly, under an embodiment.

FIG. 14 is a flow diagram for seed layer formation using oxide particlemolecular self-assembly, under an embodiment.

FIG. 15 shows example depictions of seed layer formation usingbifunctional, monofunctional, and oxide particle molecularself-assembly, under an embodiment.

FIG. 16 is a substrate processing system using molecular self-assembly,under an embodiment.

FIG. 17 is a substrate processing system using molecular self-assembly,under an alternative embodiment.

FIG. 18 is a substrate processing system using molecular self-assembly,under another alternative embodiment.

FIG. 19 is a flow diagram for using a molecular self-assembly system(MSAS) to form or produce a capping layer on electrically conductiveregions separated by a dielectric region, under an embodiment.

FIGS. 20A through 20E show cross-sectional views of an electronic deviceundergoing formation of a capping layer on electrically conductiveregions separated by a dielectric region, under the molecularself-assembly of an embodiment.

FIG. 21A shows a cross-section of a structure including a dielectricregion on which a masking layer and a capping layer are formed, usingthe molecular self-assembly of an embodiment.

FIGS. 21B through 21E show additional cross-sections of the structureduring further processing to remove the capping layer, under anembodiment.

In the drawings, the same reference numbers identify identical orsubstantially similar elements or acts. To easily identify thediscussion of any particular element or act, the most significant digitor digits in a reference number refer to the Figure number in which thatelement is first introduced (e.g., element 100 is first introduced anddiscussed with respect to FIG. 1).

DETAILED DESCRIPTION

Systems and methods for molecular self-assembly are described below foruse in forming material(s) on a substrate. The use of the systems andmethods for molecular self-assembly, collectively referred to herein as“molecular self-assembly,” enables production of very small structuresand features on substrates (e.g., at the nanometer size scale) at verylow cost, which can be useful in the commercial manufacturing of avariety of products, such as electronic components and flat paneldisplays. A system for performing molecular self-assembly is referred toherein as a “molecular self-assembly system” or “MSAS” and examples ofsuch systems are described in the Related Applications and elsewhereherein.

The molecular self-assembly described herein includes thin filmdeposition methods for use in the manufacture of integrated circuits,semiconductor devices, flat panel displays, optoelectronic devices, datastorage devices, magnetoelectronic devices, magnetooptic devices,molecular electronic devices, solar cells, photonic devices, packageddevices, and the like. The molecular self-assembly of an embodimentprovides for formation of a conformal thin film of a desired compositionand thickness on a substrate by initially forming a layer comprised ofnanometer scale particles and subsequently treating the formed layer soas to coalesce the nanometer scale particles and remove any undesiredconstituents to form a conformal thin film with the desired compositionand thickness.

The molecular self-assembly of an embodiment provides a molecularlyself-assembled layer (referred to herein as a MSAL) on a substrate. TheMSAL is formed using one or more processes described herein between atleast one dielectric material and at least one electrically conductivematerial and creates one or more of an interfacial layer, diffusionbarrier and/or adhesion layer between the dielectric(s) and electricallyconductive material(s). The MSAL is for use in forming metalinterconnections between electrical elements (e.g., transistors,capacitors) formed in or on a semiconductor substrate but is not solimited.

The MSAL of an embodiment is produced by forming a layer of material(referred to as MSAL material) on one or more regions of a dielectric,where constituents of the MSAL material have a characteristic dimensionrelative to the size of the pores in the dielectric material thatinhibits diffusion into the dielectric material. The MSAL formationcontinues with annealing of the formed MSAL to effect desired chemical,electrical, and/or mechanical changes. The MSAL of an embodiment formedin this manner can eliminate the need to provide a deposited barrierlayer together with the molecularly self-assembled layer between thedielectric and electrically conductive materials.

The MSAL of an alternative embodiment is formed on a substrate, togetherwith a deposited barrier layer, between dielectric material andelectrically conductive material, as described below. The combination ofthe MSAL together with the deposited barrier layer can produce diffusionbarrier and/or adhesion layer capabilities comparable to, or betterthan, those provided by a deposited barrier layer produced in aconventional manner (e.g., using PVD, ALD, or a combination of the two).

The MSAL of an embodiment is formed to seal pores at the surface of aporous dielectric material to prevent or inhibit diffusion of materialinto the dielectric material via the exposed pores. As an example, useof the MSAL to seal pores provides a barrier to reactants used in an ALDprocess or other chemical-based process that forms a deposited barrierlayer. The MSAL that seals pores is formed using a molecule having anappropriate inorganic or organic backbone and/or appropriate head group,as described in detail below. This pore sealing MSAL seals pores formedin a porous dielectric material so that the barrier to reactantdiffusion into the porous dielectric material is about the same as, orbetter than, that into a non-porous dielectric material (e.g. silicondioxide, FSG, etc.) without the MSAL. The pore sealing MSAL thereforeenables or facilitates use of porous dielectric materials withrelatively low dielectric constants that are increasingly being used insemiconductor substrates.

The MSAL of an embodiment provides good adhesion properties with respectto one or more materials adjacent to the MSAL (e.g., dielectricmaterial, deposited barrier layer, electrically conductive material,etc.). For example, the MSAL can provide adhesion properties between theelectrically conductive material and the dielectric material that arebetter than those provided by a conventional deposited barrier layer.The MSAL adhesion properties thus can inhibit delamination of theelectrically conductive material from the dielectric material. The MSALalso can provide good adhesion properties to a barrier layer that isformed on the MSAL. This can be accomplished, for example, by formingthe molecularly self-assembled layer using a molecule having anappropriate head group (for covalent bonding to dielectric material) andan appropriate terminal group (for covalent bonding to the barrierlayer), as described in detail below. The improved adhesion provided bythe MSAL improves the reliability of the structure and, therefore, thehost device as a result of the increased strength of the bonds at partsof the device where one or more interfaces connect an electricallyconductive material to a dielectric material (e.g., as occurs for metalinterconnections between electrical elements).

The MSAL of an embodiment can be selectively formed on a dielectricmaterial and not on any exposed electrically conductive material (e.g.,metal at the bottom of vias), as described below. The selectiveformation of the MSAL allows the MSAL to act as a passivation layerduring a subsequent wet cleaning process. The wet cleaning process, forexample a reactive wet etch process, is typically used to cleanelectrically conductive material exposed by an opening in the dielectricmaterial. The selectively formed MSAL can prevent damage to thedielectric material and/or absorption of moisture or etch chemicals intothe dielectric layer during this process.

The substrate can include any type of material or substrate, for examplesilicon substrates, silicon-on-insulator substrates, silicon carbidesubstrates, strained silicon substrates, silicon germanium substrates,and gallium arsenide substrates, etc. In particular, the molecularself-assembly of an embodiment can be used in the processing ofsemiconductor substrates as is commonly done in the manufacture ofcomponents for use in the electronics industry. The molecularself-assembly can also be used in the processing of a substrate for usein the production of a flat panel display.

The term “substrate” is used herein to refer to a material having arigid, semi-rigid, or flexible surface. In one embodiment, the substratecan include supporting material(s) (such as a wafer) upon or withinwhich a component or number of components is fabricated or to which acomponent is attached. In another embodiment, the substrate can includethe supporting material(s) and the component(s). The substrate includesfor example a plate, wafer, panel and/or disk of suitable material onand/or in which the components of a unit, such as an integrated orprinted circuit, are deposited or formed. A flexible substrate caninclude plastic or polymeric material, for example flexible materialsused in displays or other flexible integrated circuit (IC) applications.At least one surface of the substrate of embodiments will besubstantially flat, although in some embodiments it may be desirable tophysically separate synthesis regions for different materials with, forexample, dimples, wells, raised regions, etched trenches, or the like.In some embodiments, the substrate itself contains wells, raisedregions, etched trenches, etc.

The term “process” or “processing” is used herein to refer to a finitecourse of actions, operations, events, and/or changes defined by purposeor effect. “Process” or “processing” is used herein to include, but notbe restricted to, providing a processing material to a region and/ormodifying a region. Processing specifically includes physicalmodifications, chemical modifications, electrical modifications, thermalmodifications, magnetic modifications, and photolytic modifications,more specifically cleaning, surface modification, surface preparation,deposition, dispensing, reaction, functionalization, etching,planarization, chemical mechanical planarization, electrochemicalmechanical planarization, lithography, patterning, implantation, thermaltreatment, irradiation, such as infrared (IR) treatment, ultraviolet(UV) treatment, electron beam treatment, and x-ray treatment, and morespecifically electrochemical deposition, electroless deposition,physical vapor deposition, chemical vapor deposition, atomic layerdeposition, and evaporation. Processing conditions are those conditions,such as temperature, time, pressure, material phase, amount, componentratio, etc., under which processing occurs. Processing as used hereincan refer to a series of processes performed in a unique order and/orcombination to effect a desired end result, for example, to form ormodify structures, test structures, devices, integrated circuits, etc.Processing includes conditions that are those conditions such astemperature, time, pressure, material phase, amount, component ratio,etc., under which a sequence of processes occurs. Processing as usedherein further includes combinatorial process sequence integration fori) evaluating different materials, ii) evaluating different processingconditions, iii) evaluating different sequencing and integration ofprocesses (with respect to both modules within a tool and to a pluralityof tools in a process flow), and combinations thereof, for such used asin the manufacture of devices such as ICs.

The term “structure” is used herein to refer to an arrangement,organization, and/or placement of one or more parts and/or elements. Thestructure can include topographical features, such as vias, holes,lines, trenches, and test structures, useful for extracting informationabout a process, identifying process problems, and improving a processas well as device performance.

In the following description, numerous specific details are introducedto provide a thorough understanding of, and enabling description for,embodiments of the molecular self-assembly. One skilled in the relevantart, however, will recognize that these embodiments can be practicedwithout one or more of the specific details, or with other components,systems, etc. In other instances, well-known structures or operationsare not shown, or are not described in detail, to avoid obscuringaspects of the disclosed embodiments.

FIG. 1 is a flow diagram for use of a MSAL with a barrier layer inproducing 100 an interconnection (e.g., a copper interconnection)between electrical elements formed in or on a semiconductor substrate,under an embodiment. Generating 100 the interconnections includesforming 101 a structure (e.g., trenches, vias, etc.) in a dielectricmaterial (e.g., silicon dioxide). The structure can be formed forexample by etching but is not so limited. A MSAL is formed 102 on thedielectric material, as described in detail below. A deposited barrierlayer is formed 103 on the MSAL. The deposited barrier layer of anembodiment is a tantalum, tantalum nitride, tantalum carbon nitride,tungsten nitride, tungsten carbon nitride, or ruthenium layer formedusing ALD, but the embodiment is not so limited. Electrically conductivematerial is formed 104 on the deposited barrier layer to fill in viasand trenches. The electrically conductive material can include metalslike copper, ruthenium, tungsten, and/or aluminum, etc.

The electrically conductive material of an embodiment can be formed 104at one time using one process or, alternatively, the electricallyconductive material can be formed in two or more steps using two or moreprocesses. For example, the electrically conductive material of anembodiment can be formed 104 by forming a seed layer of copper (via e.g.PVD, ALD, CVD, etc.) on the deposited barrier layer and then filling thevias and trenches with copper using a bulk formation process (e.g.electroless deposition, electroplating, and combinations thereof, etc.).Alternatively, for example, if the barrier layer is formed using amaterial such as ruthenium, the electrically conductive material of anembodiment can be formed 104 by forming copper to fill the vias andtrenches in a single process.

FIGS. 2A through 2D are cross-sectional views of a substrate 200 showinguse of a MSAL in the formation 100 of interconnects between elements inor on the substrate, under an embodiment. FIG. 2A is a cross-sectionalview of the substrate 200 that includes trenches 201 and vias 202 formedin a dielectric material 203 of the substrate 200. An electricallyconducting material layer 299 (e.g., copper line) underlies thedielectric material 203 in this example. Also, the structure shown is adual damascene interconnect structure but the molecular self-assembledescribed herein is not limited to this interconnect structure. FIG. 2Bis a cross-sectional view of the substrate 200 including a MSAL 207formed on the dielectric material 203, under an embodiment. FIG. 2C is across-sectional view of the substrate 200 including a barrier layer 204formed on the MSAL 207, under an embodiment. FIG. 2D is across-sectional view of the substrate 200 including electricallyconductive material 206 formed in the trenches 201 and vias 202 over thebarrier layer 204, under an embodiment.

The MSAL of an alternative embodiment is formed on a substrate betweendielectric material and electrically conductive material, and does notinclude use of a deposited barrier layer. FIG. 3 is a flow diagram foruse of a MSAL in producing 300 an interconnection (e.g., a copperinterconnection) between electrical elements formed in or on asemiconductor substrate, under an embodiment. Generating 300 theinterconnections of an embodiment includes forming 301 one or morestructures (e.g., trenches, vias) in a dielectric material (e.g.,silicon dioxide). A MSAL is formed 302 on the dielectric material.Electrically conductive material (e.g., a metal such as copper) isformed 303 on the MSAL to fill in the vias and trenches.

The electrically conductive material of an embodiment can be formed 303at one time using one process or, alternatively, the electricallyconductive material can be formed in two or more steps using two or moreprocesses. For example, the electrically conductive material of anembodiment can be formed 303 by first forming a seed layer of copper onthe deposited barrier layer and then filling the vias and trenches withcopper using a bulk formation process. Alternatively, for example, ifthe barrier layer is formed using a material such as ruthenium, theelectrically conductive material of an embodiment can be formed 303 byforming copper to fill the vias and trenches in a single process.

FIGS. 4A through 4C are cross-sectional views of a substrate 400 showinguse of a MSAL in the formation 300 of interconnects between elements inor on the substrate, under an embodiment. FIG. 4A is a cross-sectionalview of a substrate 400 in which a trenches 401 and vias 402 are formedin a dielectric material 403 of the substrate 400. An electricallyconducting material layer 499 (e.g., copper line) underlies thedielectric material 403 in this example. Also, the structure shown is adual damascene interconnect structure but the molecular self-assembledescribed herein is not limited to this interconnect structure. FIG. 4Bis a cross-sectional view of the substrate 400 with a molecularlyself-assembled layer 407 formed on the dielectric material 403, under anembodiment. FIG. 4C is a cross-sectional view of the substrate 400including electrically conductive material 406 formed in the trenches401 and vias 402 over the molecularly self-assembled layer 407, under anembodiment.

FIG. 5 is a flow diagram for forming 500 a MSAL as a diffusion barrierand/or adhesion layer between electrically conductive and dielectricmaterials, under an embodiment. A structure(s) (e.g., trenches, vias,etc.) is formed in a dielectric material of a substrate (as describedabove), and generation of the MSAL includes preparing 501 the exposedsurface of the dielectric material prior to formation of the MSAL.Preparation 501 of the exposed surface can include preparation of thesurface of electrically conductive material exposed at the bottom of thestructure formed in the dielectric material, as described below. A layerof material is formed 502 on the dielectric material using molecularself-assembly as described herein. The MSAL can be formed as a monolayer(e.g., a self-assembled monolayer (SAM)) or a multilayer. The materialof the MSAL can be organic or inorganic material, but is not so limited.Formation 502 of the material of the MSAL can include functionalizing aterminal group of the molecularly self-assembled layer but is not solimited. Functionalization of a material as used herein refers tomodifying the characteristics of an exposed part of the material toachieve a desired interaction with another material subsequently formedon the exposed part of the material. Post-processing 503 is performed onthe material of the MSAL prior to formation of additional material(e.g., barrier layer, electrically conductive interconnect material) onthe MSAL.

Generation 500 of the MSAL can be implemented using any of a variety ofprocesses and techniques, such as are described in the RelatedApplications referenced above. For example, the MSAL can be generated500 using wet processing (e.g., immersion of a substrate in a chemicalbath, spraying or spinning of chemical fluid on to a substrate), dryprocessing (e.g., vapor deposition), and/or various combinations of wetand dry processing.

The preparation 501 of an exposed surface of a dielectric material forformation 500 of a MSAL can include one or more of a variety ofprocesses. For example, the surface of the dielectric material can becleaned using any of a variety of processes (e.g. acidic chemistries,basic chemistries, and/or combinations thereof) to remove anycontaminants (e.g. organic, inorganic, metallic, etc.) produced duringformation of the structure in which the electrically conductive materialis to be formed. These contaminants can include, for example, residualmaterial left after etching of the dielectric material or ashing used toremove photoresist.

Preparation 501 can also include functionalization of the surface of thedielectric material to inhibit the diffusion of chemicals used insubsequent processing of the substrate into the dielectric material.Functionalization can be necessary or desirable, for example, ifsubsequent processing of the substrate makes use of aggressivechemistries that may otherwise diffuse into and/or damage the dielectricmaterial. Such functionalization can itself inhibit diffusion into thedielectric material of other materials. Additionally, functionalizationof the surface of the dielectric material can facilitate selectiveformation of the MSAL on the dielectric material and/or improve theadhesion of the dielectric material to the MSAL.

The particular manner in which the dielectric material is functionalizedcan depend on the nature of the dielectric material, the nature of theMSAL to be formed, and the desired characteristics(s) (e.g., adhesionproperties) to be produced. For example, the surface of a silicondioxide-based dielectric material can be functionalized to produce alarge number of hydroxyl (i.e. OH) groups at the surface of thedielectric material to which the MSAL has an affinity for attachment,thus promoting formation of the MSAL on the dielectric material.

Surface preparation 501 can also include performing an etch process(e.g., wet process) to remove unwanted material formed on exposedelectrically conductive material (e.g., metal at the bottom of vias).The unwanted material may be present from prior processing of thesubstrate. The etch process can include, for example, a reactive etchprocess (e.g., wet) but is not so limited. Such etching can also beperformed to etch down into exposed electrically conductive material toenhance mechanical attachment of electrically conductive materialsubsequently formed thereon and improve electro-migration reliability.If the surface preparation includes such etching, then cleaning can alsobe performed again after the etching.

Regarding formation 502 of the MSAL as described above with reference toFIG. 5, the type and characteristics of the molecule(s) used to form theMSAL can be chosen to produce desired properties of the molecularlyself-assembled layer. The characteristics of the molecule can includesuch characteristics as the head group, terminal group and/or length(e.g., the number of carbon atoms in the organic backbone portion of themolecule) of the molecule. The characteristics of the MSAL of anembodiment can thus be established to produce desired adhesionproperties, pore sealing capabilities, diffusion barrier capabilities,and/or passivation capabilities of the MSAL. To produce desiredproperties of the MSAL, the manner in which the MSAL is tailored (i.e.,the characteristics that are established) can depend on the nature ofthe dielectric material on which the MSAL is to be formed and the natureof the material (e.g., deposited barrier layer) to be subsequentlyformed on the MSAL.

For example, a MSAL can be formed that seals the pores of a porousdielectric material. The porous dielectric material can have pores thatare open or closed, oriented in any direction and with any shape, andpossess various levels of interconnectivity. In addition, the volumetricpore fraction in the dielectric material can vary, typically less thanor equal to approximately 50 percent (50%) in order to maintainstructural integrity. The chain length (e.g., the number of carbon atomsformed in a chain) and/or the head group of the molecule used to formthe MSAL can be established so that the presence of the MSAL will sealsome or all of the pores at the surface of the dielectric material. Forexample, the length of the carbon chain in an organic molecule can bespecified to be long enough relative to the size (typically ranging fromgreater than or equal to approximately 10 Å to less than or equal toapproximately 25 Å in diameter) of the exposed pores at the surface of aporous dielectric material to ensure that those pores (at least anadequate number) are sealed. Additionally, the MSAL can be formed sothat the molecules are cross-linked. This can be done during formation,functionalization, or post-processing of the MSAL.

The MSAL can also be tailored to produce desired adhesion propertieswith respect to the dielectric material. In particular, the head groupof the molecule used to form the MSAL can be established to provide goodadhesion to the dielectric material. For example, a head group can beestablished that covalently bonds with an exposed hydroxyl group of adielectric material.

The MSAL can also be tailored to produce desired adhesion propertieswith respect to a material to be formed on the MSAL (e.g., a depositedbarrier layer, electrically conductive interconnect material, etc.). Inparticular, the terminal group of the molecule used to form the MSAL canbe established (e.g., the molecule specified to include a particularterminal group and/or the terminal group of a molecule functionalized)to provide good adhesion to the material to be formed on the MSAL (e.g.,deposited barrier layer). The particular terminal group used, or mannerof functionalization of a terminal group, can depend on the type ofmaterial(s) formed on the MSAL and/or the precursors, reactants, etc.used to form such material(s). As an example, a NR_(x), (e.g. NH, NH₂,NRH, etc.) terminal group, where R═H, an organic group, and/orcombinations thereof, provides good adhesion to titanium-basedmaterials, tantalum based materials, ruthenium based materials,tungsten-based materials, and/or precursors (e.g. TDMAT, TDEAT, PDMAT,TBTDET, TBTEMT, WF6, ruthenocenes and their derivatives, metalorganicprecursors, etc.) used to form such barrier layer materials.Additionally, a thiol terminal group provides good adhesion (facilitatescovalent bonding) to a copper seed layer, for example, when the MSAL isimplemented without the formation of a deposited barrier layer betweenthe dielectric and electrically conductive materials.

Molecular self-assembly of an embodiment also forms a MSAL having goodselectivity to a particular type of dielectric material (which may bewithout regard to structure or geometry) and/or to a dielectric materialhaving a particular structure or geometry. The selective MSAL will haverelatively poor affinity to other materials to which it is notselective, for example, exposed electrically conductive material (e.g.,metal at the bottom of a via). Formation of the selective MSAL of anembodiment includes, for example, forming and/or functionalizing thedielectric material on which the material of the MSAL is to be formedand performing the molecular self-assembly in a manner tailored to suchformation and/or functionalization. As an example, the dielectricmaterial can be functionalized to promote adhesion to the material ofthe MSAL, as discussed above. Forming the MSAL with good selectivity fordielectric material enables the MSAL to be formed so that it can act asa passivation layer during a subsequent wet cleaning process, preventingfor example, etching of the dielectric material, diffusion of etchingchemistries into the dielectric material, and/or damage to thedielectric material.

A MSAL is generally a layer that results from the coordinated action ofindependent molecules under distributed control. Molecular self-assemblycan refer to the joining of complementary surfaces in nano-molecularaction. The characteristics of the MSAL can be affected by the type ofmolecule used to form the MSAL. In general, a molecule can be chosen foruse in forming the MSAL depending on the particular application in whichthe MSAL is used, i.e., the nature of the dielectric material on whichthe MSAL is to be formed, the nature of the material (e.g., barrierlayer) to be subsequently formed on the MSAL, and the desiredcharacteristics(s) (e.g., adhesion properties, pore sealingcapabilities, diffusion barrier capabilities, passivation capabilities)to be produced.

For example, thiols are a type of molecule that can be used to form aMSAL in an embodiment. Thiols are advantageous in that they are verywell characterized (e.g., they are known to grow well on certainmaterials, they can include any of a number of different groups that canbe functionalized to produce particular properties). Certain thiols(e.g. R—SH, where the organic group R=alkyl, aryl, heteroaryl,functionalized alkyl, functionalized aryl, functionalized heteroaryl,etc.) can be chosen for their relative low thermal break downtemperature range (e.g. approximately 150° C.-250° C. range) which makesthem compatible with low dielectric constant and/or porous lowdielectric constant materials processing and integration where thermalbudget is a concern. For example, a thiol-based MSAL can befunctionalized with an organo-metallic terminal group that leaves onlymetal (having a sufficiently high breakdown temperature) exposed aftervaporization of the carbon species of the group. Not all thiols have lowbreakdown temperatures; for example, some thiols (e.g. R—SH, whereR=fluorinated alkyl, fluorinated aryl, etc.) have a thermal breakdowntemperature greater than about 300 degrees Celsius.

Silicon-based molecules (e.g., silanes) are an example of another typeof molecule that can be used to form a MSAL under an embodiment.Silicon-based molecules advantageously have higher breakdowntemperatures due to the formation of strong Si—O covalent bonds (e.g.,in a range of approximately 250° C. to 350° C. or above) than thiols(typically 150° C.-250° C. range). Other covalent bonds which can beformed between a substrate (e.g. dielectric) and a MSAL include Si—N,Si—C, Si—S, O to C groups, etc., and combinations thereof.

The MSAL can be formed using organosilanes R_(n)—Si—X_(4-n), where n=1,2, 3, and where the organic group R═H, alkyls, alkenyls, alkynyls,aryls, fluoroalkyls, heteroaryls, fluoroheteroaryls, alcohols, thiols,amines, amides, imines, carboxylic acids, thiocarboxylic acids,thiocarbamates, esters, ethers, sulfides, nitriles, etc. Thehydrolyzable group X=halides (Cl, F, Br, I, etc.), carboxylates(—O—CO—R¹), amines (—NR²R³), alkoxides (—O—R⁴, e.g. methoxide, ethoxide,propyloxide, butoxide, phenyloxide, etc.), sulfides (—S—R⁵),heteroaryls, fluororoaryls, etc., and R¹, R², R³, R⁴, R⁵ can beindependently selected organic groups (e.g. alkyl, aryl, etc.) asdescribed above for R. The organic substituent R can be selected fromlinear and/or branched groups having from 1 to about 30 or more carbonatoms.

The organic group R_(n) is comprised of a terminal group (i.e. tailgroup) and a linking (i.e. linker) group. The linker connects the headgroup (e.g. Si atom) to the terminal group. The linker can be of theform (CH₂)_(n), whereby, n=0, 1, 2, 3, 4 . . . or higher, etc. and canbe chosen to tailor the effective length and/or size of the MSAL. Theterminal group is attached to the “tail end” of the linker. The terminalgroup can be chosen for particular chemical properties and/or affinityto the subsequent material to be deposited over the MSAL. The terminalgroup can also be used to adjust the effective size and/or length of theMSAL. In some embodiments, the linker and the terminal group are part ofand/or are the same substituent. The hydrolyzable group (e.g. leavinggroup) X can be used to adjust the reactivity of the organosilane to thesubstrate of interest to effect deposition. The hydrolyzable group, inparticular, reacts with the surface hydroxyl groups (OH) of thesubstrate to form the MSAL layer and is liberated in the formationprocess. Certain dielectric films (e.g. substrates) have varying amountsof surface hydroxyl groups. The terminal and/or linking groups can bechosen to account for the lower number of hydroxyl attachment sites bychoosing polymerizable substituents and/or larger and/or branchedsubstituents (e.g. phenyls, adamantanes, dendrimers, star polymers,etc.).

For cases when n=1, i.e. R—Si—X₃, the silanes tend to oligomerize,polymerize and/or crosslink, etc. during and/or after deposition on thesubstrate. This can result in a more thermally, chemically, and/orphysically stable MSAL layer, in particular after a drying and/or curingprocess. This can also be advantageous when the MSAL layer is used toseal the exposed pores of porous dielectric materials. FIG. 6A shows anorganosilane 600 that includes three hydrolyzable groups, under anembodiment. The terminal group 602 (e.g. organofunctional or functionalgroup), the linker 604, the silicon head group 606, and the hydrolyzablegroups 608 of the organosilane 600 are shown. FIG. 6B shows a MSALformation process 610 using an organosilane with three hydrolyzablegroups, under an embodiment. The MSAL formation process 610 includeshydrolysis 620, condensation 640 (e.g. oligomerization, polymerization,and/or crosslinking, etc.), hydrogen bonding 660, and bond formation 680(via e.g. drying, and/or curing, etc.), but is not so limited.

Water used for hydrolysis 620 of the organosilane can be from thesubstrate (e.g. on the surface), the ambient, and/or deliberatelyintroduced. Alternatively, surface hydroxyl groups of the substrate(e.g. dielectric material) can also enable the hydrolysis reaction 620.The free hydroxyl groups of the silane can condense 640 to formoligomers, polymers, etc. which in turn can attach to the surface of thesubstrate via hydrogen bonding 660. Finally, dehydration via dryingand/or curing, etc. can be used to induce bond formation 680 between thenow deposited MSAL layer and the substrate. In particular, the Siliconhead group (“—Si-”) can covalently bond to the surface of the substratevia such a bond formation process. Some particular examples ofpolymerizable organosilanes include but are not limited to C₁₂H₂₅SiCl₃and C₁₈H₃₇Si(OCH₃)₃. Silanes with n=2, i.e., R¹R²—Si—X₂, can also beused to form the MSAL.

For cases when n=3, i.e., R¹R²R³—Si—X, the silanes do not tend tooligomerize, polymerize and/or crosslink, etc. during and/or afterdeposition on the substrate which may lead to lower undesired byproductsformation. An example includes R¹R²R³—Si—X, where X═OR′, NR¹R², Cl, etc.In an embodiment, the organosilanes with one hydrolyzable group arepreferred for anhydrous (e.g. when external source(s) of water is notused) environments. The surface hydroxyl groups of the substrate candrive the MSAL formation process. FIG. 7 is an example of MSAL formation700 using an organosilane with one hydrolyzable group, under anembodiment. Silanes including the R¹R²R³—Si—X type can also behydrolyzed to form free OH, and/or di-merize to di-siloxanes which inturn can react with the free hydroxyl species of the substrate materialto form the MSAL.

Organosilanes which do not produce any corrosive byproducts (e.g. HCl,HF, HBr, etc.) are used as such corrosive byproducts may corrode orotherwise damage conductive and/or metallic surfaces (e.g. copper,cobalt containing layers, tantalum containing layers, etc.).Organosilanes can be chosen with benign leaving (hydrolyzable) groupslike alkoxy or amines. Octadecyldimethyl(dimethylamino)silaneC₁₈H₃₇(CH₃)₂Si—N(CH₃)₂ and dodecyldimethyl(methoxy)silaneC₁₂H₂₅(CH₃)₂Si—OCH₃ are some preferred embodiments. Trimethoxysilanesand triethoxysilanes are other preferred embodiments.

All the aforementioned organosilanes can be tailored to form covalentbonds to hydroxyl (OH) containing substrates (e.g. dielectrics) bymanipulating the hydrolizable groups of the organosilanes.

Dendrimers, hyper-branched polymers, polymer brushes, and blockco-polymers can also be used to form a MSAL under an embodiment.Additionally, ionic or electrochemically-enhanced self-assembledmultilayers or monolayers can embody a MSAL. Each of the foregoing canbe used to form a MSAL that has good diffusion barrier properties(including pore sealing and diffusion barrier capabilities) and has goodadhesion to many types of dielectric materials.

As indicated above, the characteristics of the MSAL (e.g., the type ofmolecule used to form the MSAL and the characteristics of the molecule,such as the head group, terminal group and/or length, etc.) can beestablished to produce desired properties of the molecularlyself-assembled layer. The desired properties can include but are notlimited to adhesion properties, pore sealing capabilities, diffusionbarrier capabilities, and passivation capabilities. Further, thecharacteristics of the MSAL needed to produce desired properties candepend on the nature of the dielectric material on which the MSAL is tobe formed and the nature of the material (referred to hereinafter as theoverlying material) to be subsequently formed on the MSAL. Thus, given aparticular dielectric material and overlying material, thecharacteristics of the MSAL can be established based on a specificationof the desired properties of the MSAL. This can be done in a number ofways, some of which are described below.

Specification of a desired property of the MSAL can be made byidentifying an allowable value or range of values for one or moremetrics that represent the presence or absence of that property in theMSAL. The characteristics of the MSAL (e.g., type of molecule type,molecule head group, molecule tail group, molecule length) can then beestablished, for example, as a set of characteristics that produceallowable value(s) for the metric(s) for each property being specifiedfor the MSAL (e.g., adhesion propert(ies), pore sealing capability,diffusion barrier capability, passivation capability).

The desired properties for a MSAL can have different degrees ofimportance. This may be reflected, for example, by the use of aparticular property or properties to screen sets of characteristics inorder to identify candidate sets of characteristics (and, perhaps, bysuccessively screening sets of characteristics for a series ofproperties in order of decreasing importance). For example, in someembodiments, the desired properties of the MSAL are good pore sealingcapability, good adhesion properties (both to the dielectric and to theoverlying layer), good diffusion barrier capability and good passivationcapability, listed in order of decreasing importance. In suchembodiments, possible characteristics for a MSAL could be identified byidentifying a first group of sets of characteristics (each set ofcharacteristics can include, for example, a particular type of molecule,molecule head group, molecule tail group and molecule length) that canproduce desired pore sealing capability. From the first group, a secondgroup of sets of characteristics is identified that can produce desiredadhesion properties. Continuing, a third group of sets ofcharacteristics is identified from the second group that can producedesired diffusion barrier capability and, from the third group, a fourthgroup of sets of characteristics is identified that can produce desiredpassivation capability. The fourth group of sets of characteristicsrepresents the possible characteristics for the MSAL for a particularapplication, from which a particular set of characteristics can bechosen for use in that application.

The post-processing 503 of the MSAL, described above with reference toFIG. 5, includes cleaning of the substrate (e.g., cleaning with TMAH,TBAH, TPAH, LiOH, KOH, and other high pH chemistries, deionized waterrinse, IPA rinse, N2 dry) to remove any undesired material (e.g.,unreacted molecules used in formation of the molecularly self-assembledlayer). In some circumstances, the cleaning can be effected in such afashion so as to remove a substantial portion (e.g., from about 50 Å to400 Å, and more preferably from about 100 Å to 250 Å) of the copper atthe bottom of the vias or structures of the substrate. This removal ofportions of copper from structure bottoms can be used to create theframework for the formation of structural anchors which can be filledduring subsequent barrier layer deposition, seed layer deposition, andbulk copper fill. These structural anchors serve to improve (e.g.,lower) via resistance and/or via resistance distribution (e.g., tighterdistribution), relieve stress concentrations at the via bottom corners,and can provide improved reliability (e.g. improved electromigrationand/or stress migration resistance). The post-processing can alsoinclude other processes as appropriate to the MSAL.

The post-processing 503 can also include a reactive etch process (e.g.,wet) using nitric or citric acid for example. This can be done, asdescribed above, to remove unwanted material formed on exposed areas ofelectrically conductive material. The etching can also be performed toetch down into exposed electrically conductive material to enhancemechanical attachment of electrically conductive material subsequentlyformed thereon and improve electro-migration reliability. When thepost-processing includes etching, cleaning can be performed after theetching. In another embodiment, the MSAL can be used as a sacrificiallayer which can be removed after the exposed electrically conductivematerial (e.g. via bottoms) has been cleaned and/or etched.

The post-processing can also include one or more of a vaporization,annealing and/or curing (e.g., electron beam or ultraviolet radiationcuring) process under an embodiment. For example, as described abovewith reference to FIG. 3, a layer of MSAL material can be formed andannealed to provide a good barrier to diffusion of material (e.g.reactants, precursors used in ALD, CVD, and the like) into a porousdielectric material. The MSAL is formed with material having acharacteristic dimension similar to the size of the exposed pores(typically a maximum of 20-50 Å in diameter, but more typically, rangingfrom greater than or equal to approximately 10 Å to less than or equalto approximately 25 Å in diameter) in the dielectric material so as toseal and hence, inhibit material diffusion into the dielectric material.The MSAL can comprise organic material(s) possessing carbon chain(s)wherein the length(s) of said carbon chain(s) can be adjusted toeffectively control the size of the organic material(s) so as to matchthe pore size and size distribution of the dielectric material andeffect efficient sealing of the exposed pores or at least a specifiedpercentage of the exposed pores at the surface of a dielectric material.In an embodiment, the MSAL can be formed using an organic materialhaving a carbon chain with a length greater than approximately 20 Å orgreater than approximately 50 Å for example. In a particular embodiment,the molecularly self-assembled layer can be formed using an organicmaterial having a carbon chain including a number of atoms approximatelyin a range of 6 to 25 atoms but is not so limited. In anotherembodiment, the MSAL can be formed using an organic material having acarbon chain with a length ranging from approximately 10 Å to 30 Å.

The MSAL material is annealed after formation for a time and at atemperature sufficient to break down the MSAL material (e.g., to breakdown the carbon chain(s) of a MSAL made of an organic material) so thatparts of the MSAL seal pores in the underlying dielectric material. TheMSAL could be functionalized prior to annealing to include a terminalgroup that, once the MSAL is broken down, provides a surface havingdesired adhesion characteristics to facilitate subsequent formation ofmaterial on the MSAL (e.g., a metal oxide terminal group can form anucleation surface for ruthenium subsequently formed on the molecularlyself-assembled layer using ALD). The annealing of MSAL material of anembodiment enables large molecules (including, but not limited to, theuse of clusters of atoms, clusters of functionalized atoms,nanoparticles, functionalized nanoparticles, and the like) to be used informing the MSAL; this can enhance the sealing of pores in a porousdielectric material while providing a relatively thin MSAL whichfacilitates implementation in increasingly small structures.Additionally, the thickness of the MSAL prior to annealing can betailored to ensure continuity of the MSAL after annealing. Further,materials that break down at relatively low temperatures (which wouldotherwise make those materials unusable for some applications) can beused in forming a MSAL.

As described above, the manufacture of integrated circuits,semiconductor devices, flat panel displays, optoelectronic devices, datastorage devices, magnetoelectronic devices, magnetooptic devices,molecular electronic devices, solar cells, photonic devices, packageddevices, and the like require the use of thin film depositiontechniques. Many of the thin film deposition techniques including butnot limited to evaporation, laser ablation, e-beam evaporation, physicalvapor deposition (PVD) or sputtering, ionized PVD, molecular beamepitaxy (MBE), and their derivatives used for such manufacturing allowthe formation of substantially pure films with controlled compositionsas the deposition species are essentially generated from sourcematerial(s) substantially representing the desired composition of theresulting deposited film. Moreover, these deposition techniquesgenerally rely on the transport of the deposition species in vapor formfrom the source material(s) to the substrate to be coated, whereby thedeposition process is essentially line-of-sight. As a result, theseaforementioned techniques suffer from step coverage and conformalityissues (e.g. the ability to deposit a film of uniform thicknessregardless of the geometry of the substrate and/or features on thesubstrate to be coated with said film) as the deposition profile isdependent on the flux and angular distribution of the incomingdeposition species. The step coverage and conformality issues areexacerbated when high aspect ratio (i.e. ratio of feature depth towidth) submicron dimension structures (e.g. lines, trenches, vias,holes, and combinations thereof) need to be covered.

Other thin film deposition techniques such as chemical vapor deposition(CVD), plasma enhanced chemical vapor deposition (PECVD),sub-atmospheric chemical vapor deposition (SACVD), metal organicchemical vapor deposition (MOCVD), laser assisted or induced CVD, e-beamassisted or induced CVD, atomic layer deposition (ALD), plasma enhancedatomic layer deposition (PEALD), ion induced atomic layer deposition,and their derivatives may provide in principle advantages in improvedstep coverage and conformality as these processes are not generallyline-of-sight but substantially rely on chemical reaction pathway(s)which can be tailored to be substantially less sensitive to the geometryof the substrate and/or features on the substrate to be coated. However,these deposition techniques suffer from the complexities associated withthe gaseous precursor(s) and chemical reaction pathway(s) required tocreate the thin film which make the formation of substantially purefilms of desired composition(s) difficult.

Many of the aforementioned techniques do not offer adequate control ofdeposition thickness as they can be generally classified as flux and/ortime dependent processes as opposed to self-limiting (as in the case forALD and its derivatives). As device feature geometries decrease, theability to accurately control the thickness of the deposited thin filmsbecomes increasingly important. These films may be less than or equal toabout 100 Å, and more specifically less than or equal to about 50 Å, andin some cases less than or equal to about 20 Å.

Moreover, the aforementioned techniques generally require operationunder specified environments ranging from sub-atmospheric (less than 760torr pressure) through vacuum levels as low as 10⁻⁸ torr or belowpressures. In addition, many of the aforementioned techniques requirethe use of plasmas or plasma environments. Operation under vacuum and/orthe need for plasmas pose additional manufacturing cost, throughout,scaling, and/or other implementation challenges which increase inseverity as the size of the substrate increases.

The molecular self-assembly of an embodiment provides a number of thinfilm deposition methods which enable for example compositional control,formation of pure films, formation of highly conformal films, accuratecontrol of film thickness, and scaling to increasing substrate sizes.The thin film deposition methods enabled under the molecularself-assembly described above include molecularly self-assembled layersfor pore sealing, improved copper interconnect integration, and copperseed layer formation as more specific examples. Each of these thin filmdeposition methods are described in detail below.

The MSAL of an embodiment provides a method for sealing exposed pores oflow-k dielectric materials. The use of low dielectric constant (i.e.low-k) materials enable reduction in RC delay, line-to-line capacitance,and power consumption for advanced interconnect technologies such as forcopper interconnects. One of the primary means of reducing thedielectric constant is through the introduction of pores or porosity inthe dielectric film. This becomes increasingly important for achievingfilms with dielectric constants less than or equal to approximately 2.5,and more specifically for dielectric constants less than or equal toapproximately 2.2. A major challenge in using porous low-k dielectricsin advanced interconnects is their integration with subsequentprocessing steps.

As an example, porous low-k dielectrics are susceptible to precursorpenetration during barrier layer formation such as in atomic layerdeposition (ALD), chemical vapor deposition (CVD), and other vapor phasedeposition processes. This can lead to poisoning of the low-kdielectric, an increase in the effective dielectric constant of thelow-k, the inability to form a continuous barrier layer over the low-k,the inability to form a thin and continuous barrier layer over thelow-k, etc., all of which can subsequently lead to poor deviceperformance. Porous low-k dielectrics also typically exhibit poor (e.g.,weaker) adhesion characteristics to barrier layers and/or liners (e.g.,Ta, Ta_(x)C_(y), Ta_(x)N_(y), Ta_(x)C_(y)N_(z), W, W_(x)C_(y),W_(x)N_(y), W_(x)C_(y)N_(z), Ru, etc.) as compared to standarddielectrics (e.g. SiO₂, FSG, etc.) which can lead to poor devicereliability (e.g. degradation in stress migration resistance and/orelectromigration resistance).

Plasma techniques (e.g., post-etch treatments) can be used to modify theexposed surfaces of the porous low-k material so as to effectively closethe pores. However such techniques often lead to structural damageand/or effective chemical damage (e.g., removal of Si—C, Si—CHx, etc.type bonds and conversion to Si—O, Si—OH type bonds) to the near surfacelayer (ranging from 50 Å to 200 Å in depth) so as to increase theeffective dielectric constant to make implementation of the porous low-kdielectric unattractive. Other techniques require the deposition of aconformal physical layer to effectively seal the exposed pores. Suchtechniques require a subsequent etch-back step to remove the materialfrom the bottom of vias, and the subsequent etch-back step adds to costand complexity, may undesirably also “de-seal” the bottom of trenches,and still may suffer from precursor penetration when an ALD or CVDrelated process is used to deposit such a conformal sealing layer.

Another approach is to choose ALD or CVD precursors with largermolecular sizes approaching that of the exposed pores such that theprecursor molecules do not readily diffuse into the exposed pores.However, this greatly limits the precursors which can be used andprecludes precursors which may be more cost-effective and/or desired inthe formation of the barrier layer and/or liner with the desiredmaterials and/or electrical properties.

The molecular self-assembly described herein provides a method forsealing the exposed pores of porous low-k dielectrics and/or improvingthe adhesion properties of porous low-k dielectrics to barrier layersused in copper interconnect formation without any undesired physicaland/or chemical damage to the porous low-k dielectric. The molecularself assembly also allows for selective sealing without undesiredmaterial formation on conductive surfaces.

FIG. 8 is a flow diagram for sealing 800 porous low-k dielectrics, underan embodiment. These porous low-k dielectrics can be used for example inthe formation of copper interconnects. The pore sealing 800 of anembodiment includes removing 802 organic and metallic contamination fromexposed dielectric surfaces by delivering cleaning solution(s) to atarget material like exposed dielectric surfaces. Copper oxide andcontamination are removed 804 from exposed copper surfaces usingdelivered cleaning and/or reducing solution(s). A molecularlyself-assembled layer(s) is formed 806 on the exposed dielectric surfacesso as to substantially fill and/or seal the exposed pores of the exposeddielectric surfaces. The MSAL is formed by delivering wetting,functionalization, and/or coating agents to the exposed dielectricsurfaces. Contamination and/or residue is removed 808 from exposedcopper surfaces using cleaning solution(s) delivered 808 to thesubstrate; the contamination and/or residue results from formation 806of the MSAL. The substrate is then rinsed 810 and dried 812. Anyoptional post-processing 814 treatment(s) (e.g., thermal, UV, IR, etc.)is then performed on the dried substrate.

The molecular self-assembly of an embodiment provides a method forimproved copper interconnect integration. Copper damascene (singleand/or dual) interconnect formation requires the cleaning of the bottomsof vias to enable good adhesion (e.g., barrier layer to underlyingcopper), electrical performance (e.g., low contact and/or viaresistance), and reliability performance (e.g., stress migration and/orelectromigration resistance).

A typical interconnect integration scheme used is as follows: degas(e.g. thermal vacuum anneal); plasma-based preclean (e.g. reactive,physical, and/or combinations thereof); barrier layer deposition (e.g.PVD TaN, Ta, and/or combinations thereof); copper seed layer deposition(e.g. PVD Cu, ALD Cu, CVD Cu, and/or combinations thereof); and bulkcopper fill (e.g. electroplating, electroless Cu deposition, and/orcombinations thereof). An issue with this typical process is thatcopper, copper oxide, carbonaceous post etch residue, and/or othercontamination removed from the bottom portions of the via during thepreclean process may be undesirably re-deposited on the sidewalls of thevia during the preclean process. The re-deposited copper can diffuseinto the dielectric and cause device performance and/or reliabilityissues (e.g. leakage and/or poor time dependent dielectric breakdown orTDDB performance). In addition, the undesirably re-deposited material(s)may lead to poor adhesion of the subsequent barrier layer to thedielectric leading to poor device performance and/or reliability issues(e.g. poor stress migration resistance).

Attempts to avoid the above-stated issues include performing thepreclean step (either in-situ in a PVD chamber or in a separate plasmabased preclean chamber) following the initial deposition of a PVDbarrier layer in a resputtering process wherein the initially depositedbarrier layer will serve as to protect the dielectric via sidewalls. Theissue with this approach is that the effective extent of materialremoved from the bottom of vias is size-dependent and aspectratio-dependent as both the initially deposited barrier layer (e.g.generally more material is deposited on the bottom of wide, low ARfeatures as compared to small, high AR features for a given PVD barrierlayer deposition process on a substrate containing both feature types)and the subsequent etching (e.g. generally the extent of punch throughat the bottom of wide, low AR features occurs is less than that at thebottom of small, high aspect ratio features) are both geometry and/oraspect ratio dependent.

FIG. 9 shows examples that the effective extent of material removed fromthe bottom(s) of vias (and/or trenches) is size-dependent and aspectratio-dependent. If a particular interconnect layer contains forexample, both wide, low aspect ratio vias 902 (e.g. 0.25 m diameter, 2:1AR vias) and small, high aspect ratio vias 904 (e.g. 0.1 m diameter, 5:1AR vias), the requirement to be able to punch through the initial layerof barrier material at the bottom of the wide, low AR vias 902 in orderto effect desired via bottom cleaning can cause removal of excessmaterial and/or damage 942 to the bottom portions of the small, high ARvias 904 leading to poor reliability. If optimal removal is targeted forthe small, high AR vias 904, then the wide, low AR vias 902 may notreceive sufficient cleaning leading to poor via resistance and/or poordevice reliability such as poor stress migration resistance due toremaining contamination 922 at the bottom of the via 902. Moreover, therequirement to be able to punch through the initial layer of barriermaterial at the bottom of the wide, low AR vias 902 in order to effectdesired via bottom cleaning may also cause the complete removal ofbarrier material and/or dielectric loss and damage 962 at the bottom ofsmall, high aspect ratio trenches 906. This can lead to devicereliability issues such as poor electromigration resistance.

Similar excess barrier removal and/or dielectric loss/damage can occuron the other horizontal surfaces such as the field which can lead tosubsequent integration challenges due to dielectric roughening and/orpoor device performance due to increased layer-to-layer capacitances.Furthermore, all of the above issues become further exacerbated when thefeatures to be cleaned are formed in low-k films with dielectricconstants less than or equal to approximately 2.5, and more specificallyfor dielectric constants less than or equal to approximately 2.2. Low-kfilms are generally of lower density and exhibit lower structuralintegrity as compared to standard dielectrics such as SiO₂ and/or FSGand hence are more easily removed, damaged, and/or roughened.

The molecular self-assembly of an embodiment provides a method forimproved copper interconnect integration that effects proper cleaning offeatures (especially of via bottoms) independent of feature geometryand/or aspect ratio, without dielectric loss/damage, and withoutre-deposition of undesired material(s) removed and/or generated duringthe cleaning process. The molecular self-assembly achieves the abovedesired aspects through the use of a sacrificial masking layer on thepatterned dielectric surfaces as described below and in the RelatedApplications referenced above.

FIG. 10A is a flow diagram for interconnect integration 1000 usingmolecular self-assembly, under an embodiment. The interconnectintegration 1000 of this example is copper interconnect integration butthe molecular self-assembly described herein is not limited to copperinterconnects. The interconnect integration 1000 of an embodimentincludes forming 1002 a masking layer on the dielectric portions of thesubstrate by delivering 1002 wetting, functionalization, and/or organiccoating agents to the substrate. The copper oxide and othercontamination is removed 1004 from exposed copper surfaces and/or aportion of the exposed copper at the bottom portions of the vias isremoved using cleaning, reducing, and/or etching solution(s) deliveredto the substrate. The sacrificial masking layer is removed 1006 usingcleaning and/or etching solution(s) delivered to the substrate.Sacrificial masking layer removal 1006 removes contaminants whichotherwise would have been re-deposited over the dielectric portion(s) ofthe substrate. Removal 1006 of the sacrificial masking layer removesre-deposited material(s) such as copper, copper oxide, carbonaceous postetch residue, and/or other contamination removed from the bottomportions of the vias during removal 1004 of the copper oxide and othercontamination from exposed copper surfaces, and/or a portion of theexposed copper. The substrate is then rinsed 1008 and dried 1010.

Other processes 1012 like barrier layer deposition, copper seed layerdeposition, and/or bulk copper fill processes can be performed followingthe interconnect integration 1000. Cleaning solution(s) can beoptionally used to remove organic and/or metallic contamination fromexposed dielectric surfaces prior to masking layer formation 1002.

FIGS. 10B-10F show an example of interconnect integration 1000 usingmolecular self-assembly, under an embodiment. FIG. 10B shows a substrate1020 that includes a dielectric material 1050 comprising vias 1052 andtrenches 1054, under an embodiment. The copper surfaces and/or portionsof copper surfaces 1056 at the bottom portion or region of the vias 1052are covered with contaminants 1024 that include oxides and/or othermaterials. The interconnect integration 1000 of an embodiment includesforming a masking layer 1022 on the dielectric portions 1050 of thesubstrate 1020 by delivering wetting, functionalization, and/or organiccoating agents to the substrate. FIG. 10C is the substrate 1020 with theformed masking layer 1022, under an embodiment.

The contamination 1024 is removed 1024R from the exposed copper surfaces1056 and/or a portion of the exposed copper at the bottom portions orregions of the vias 1052 is removed using cleaning, reducing, and/oretching solution(s) delivered to the substrate. FIG. 10D is thesubstrate 1020 following removal of the contamination 1024 from thebottoms of the vias 1052, under an embodiment. Some amount of thecontamination 1024R removed from the via bottom regions is trapped onand/or in the masking layer 1022. The sacrificial masking layer 1022 isremoved using cleaning and/or etching solution(s) delivered to thesubstrate. Removal of the sacrificial masking layer removes material(s)1024R such as copper, copper oxide, carbonaceous post etch residue,and/or other contamination removed from the bottom portions of the viasduring removal 1004 of the copper oxide and other contamination. FIG.10E is the substrate 1020 following removal of the masking layer 1022and the contamination 1024 and 1024R, under an embodiment. As describedabove, other layers 1030 (e.g., barrier layer, copper seed layer) canthen be formed on the substrate and/or the exposed material at thebottom portions of the vias 1052. FIG. 10F is the substrate 1020following optional processing to form other layers 1030 (e.g., barrierlayer is shown), under an embodiment.

The liquid-based via bottom clean described above for copper oxide andcontamination removal 1004 can be made to be geometry and/or aspectratio independent. Wetting agents and/or surfactant can be used topromote uniform reaction. Since physical sputtering is not employed,dielectric loss and/or damage are avoided. The sacrificial masking layerprovides a means by which material(s) such as copper, copper oxide,carbonaceous post etch residue, and/or other contamination removed fromthe bottom portions of the vias during contamination removal 1004 (whichwould otherwise have been re-deposited over the dielectric portion(s))are removed through the removal of the masking layer.

Furthermore, the sacrificial masking layer can serve to protect thedielectric during via bottom cleaning. In some circumstances, thecleaning can be effected in such a fashion so as to remove a substantialportion (e.g. from approximately 50 Å to 400 Å, and more preferably fromapproximately 100 Å to 250 Å) of the copper at the bottom of the vias.This can be used to create the framework for the formation of structuralanchors which can be filled during subsequent barrier layer deposition,seed layer deposition, and bulk copper fill. These structural anchorsserve to improve (e.g. lower) via resistance and/or via resistancedistribution (e.g. tighter distribution), relieve stress concentrationsat the via bottom corners, and can provide reliability advantages (e.g.improved electromigration and/or stress migration resistance).

The molecular self-assembly of an alternative embodiment provides amethod for improved copper interconnect integration that deposits anelectroless metal alloy after cleaning the via bottoms. The electrolessmetal alloy, which can include materials like a cobalt containing alloy,CoW, CoWP, CoWB, CoB, CoBP, CoWBP, Ni containing alloys, etc.,passivates and protects the now cleaned copper surfaces at the bottom ofthe vias. This provides an improved adhesion layer, hermetic layer,barrier layer, and/or reliability enhancement layer (e.g. for stressmigration resistance and/or electromigration resistance) but is not solimited.

FIG. 11A is a flow diagram for interconnect integration 1100 usingmolecular self-assembly, under an alternative embodiment. Theinterconnect integration 1100 of an embodiment includes forming 1102 amasking layer on the dielectric portions of the substrate by deliveringwetting, functionalization, and/or organic coating agents to thesubstrate. The copper oxide and other contamination is removed 1104 fromexposed copper surfaces and/or a portion of the exposed copper at thebottom portions of the vias is removed using cleaning, reducing, and/oretching solution(s) delivered to the substrate. Electroless plating 1106of a metal alloy capping layer over the exposed copper surface at thebottom portions of the vias is effected through delivery of amulti-component plating chemistry to the substrate. The multi-componentplating chemistry of an embodiment includes but is not limited to Cocontaining agents, Ni containing agents, transition metal containingagents, reducing agents, pH adjusters, surfactants, wetting agents, DIwater, DMAB, TMAH, etc.

Contamination and/or excess plating material is removed 1108 usingpost-cleaning solution(s) delivered to the substrate following theelectroless plating 1106. The sacrificial masking layer is then removed1110 using cleaning and/or etching solution(s) delivered to thesubstrate. Removal 1110 of the sacrificial masking layer removes i)re-deposited material(s) such as copper, copper oxide, carbonaceous postetch residue, and/or other contamination removed from the bottomportions of the vias during removal 1104 of the copper oxide and othercontamination from exposed copper surfaces, and/or a portion of theexposed copper, ii) contamination resulting from the electroless plating1106, and/or iii) contamination resulting from the post plating clean1108. Masking layer removal 1110 removes contaminants which otherwisewould have been re-deposited over the dielectric portion(s) of thesubstrate. Removal 1108 of contamination and/or excess plating materialand removal 1110 of the sacrificial masking layer can be performed in asingle removal process or operation but are not so limited.

The substrate is rinsed 1112 and dried 1114 following removal 1110 ofthe sacrificial masking layer. Other processes 1116 like barrier layerdeposition, copper seed layer deposition, and/or bulk copper fillprocesses can be performed following the interconnect integration 1100.Cleaning solution(s) can be optionally used to remove organic and/ormetallic contamination from exposed dielectric surfaces prior to maskinglayer formation 1102.

FIGS. 11B-11G show an example of interconnect integration 1100 usingmolecular self-assembly, under an embodiment. FIG. 11B shows a substrate1120 that includes a dielectric material 1150 comprising vias 1152 andtrenches 1154, under an embodiment. The copper surfaces and/or portionsof copper surfaces 1156 at the bottom portion of the vias 1152 arecovered with contaminants 1124 that include oxides and/or othermaterials. The interconnect integration 1100 of an embodiment includesforming a masking layer 1122 on the dielectric portions 1150 of thesubstrate 1120 by delivering wetting, functionalization, and/or organiccoating agents to the substrate. FIG. 11C is the substrate 1120 with theformed masking layer 1122, under an embodiment.

The contamination 1124 is removed 1124R from the exposed copper surfaces1156 and/or a portion of the exposed copper at the bottom portions ofthe vias 1152 is removed using cleaning, reducing, and/or etchingsolution(s) delivered to the substrate. FIG. 11D is the substrate 1120following removal of the contamination 1124 from the bottoms of the vias1152, under an embodiment. Some amount of the contamination 1124Rremoved from the via bottoms is trapped on and/or in the masking layer1122.

Electroless plating forms a metal alloy capping layer 1132 over theexposed copper surface at the bottom portions of the vias is effectedthrough delivery of a multi-component plating chemistry to thesubstrate. FIG. 11E is the substrate 1120 following formation of thecapping layer 1132, under an embodiment. Contamination and/or excessplating material is removed following the electroless plating and thesacrificial masking layer 1122 is removed using cleaning and/or etchingsolution(s) delivered to the substrate. Removal of the sacrificialmasking layer 1122 removes material(s) 1124R such as copper, copperoxide, carbonaceous post etch residue, and/or other contaminationremoved from the bottom portions of the vias during removal 1104 of thecopper oxide and other contamination. FIG. 11F is the substrate 1120including the capping layer 1132 following removal of the masking layer1122 and the contamination 1124 and 1124R, under an embodiment. Asdescribed above, other layers 1130 (e.g., barrier layer, copper seedlayer) can then be formed on the substrate and/or the exposed materialat the bottom portions of the vias 1152. FIG. 11G is the substrate 1120following optional processing to form other layers 1130 (e.g. barrierlayer is shown), under an embodiment.

The molecular self-assembly of an embodiment provides a method forforming a copper seed layer as described below. Copper interconnecttechnology relies on the use of a copper seed layer to act as thenucleation layer for subsequent copper bulk fill by electrochemicaldeposition or electroplating and serves to carry the plating current.The copper seed layer should be thin, conformal, continuous, and possesssufficient film purity to achieve good adhesion to the underlyingbarrier material (e.g., tantalum and its nitrides, ruthenium, tungstenand its nitrides, titanium nitride, tantalum carbon nitride, tungstencarbon nitride, etc.). Furthermore, the copper seed layer should notdegrade the electrical performance (e.g. effective copper resistivity,EM resistance, stress migration resistance, etc.) of the interconnectstructure. PVD techniques suffer from inadequate step coverage and/orpoor film conformality which lead to void formation duringelectroplating and subsequent device reliability issues. CVD Cutechniques offer conformality, but suffer from impurity incorporation(e.g., F, Cl, C) which lead to poor adhesion and electrical performance(e.g., via resistance, EM resistance, stress migration resistance) ascompared to PVD. In addition, nucleation issues make the formation of athin continuous film of less than or about 200 Å difficult. ALD Cusuffers from similar impurity and nucleation issues as CVD Cu.

The molecular self-assembly of an embodiment provides a process for usein forming a copper seed layer. The copper seed layer can be formedusing a bifunctional process, a monofunctional process, or an oxideprocess. FIG. 12 is a flow diagram for seed layer formation usingbifunctional molecular self-assembly 1200, under an embodiment. Thesubstrate is initially cleaned 1202 to remove any unwanted impuritiessuch as organic and/or metallic contamination. Once the substrate iscleaned, the functionalized nanoparticles are deposited 1204 on thecleaned substrate. The functionalized nanoparticles are self-bonding tothe substrate and represent the thickness target of the desired thinfilm. One or more post-processing treatment(s) 1206 are then performedon the substrate.

FIG. 13 is a flow diagram for seed layer formation using monofunctionalmolecular self-assembly 1300, under an embodiment. The substrate isinitially cleaned 1302 to remove any unwanted impurities such as organicand/or metallic contamination. Once the substrate is cleaned, thesubstrate is functionalized 1304 as described above. Thefunctionalization 1304 creates for example desired bonding sites formonofunctional copper and/or other nanoparticles. Copper nanoparticlesrepresenting the thickness target of the desired thin film are deposited1306 on the substrate. One or more post-processing treatment(s) 1308 arethen performed on the substrate.

FIG. 14 is a flow diagram for seed layer formation using oxide particlemolecular self-assembly 1400, under an embodiment. The substrate isinitially cleaned 1402 to remove any unwanted impurities such as organiccontamination. Once the substrate is cleaned, the oxide nanoparticlesare deposited 1404 on the cleaned substrate. The oxide nanoparticlesupon reduction are self-bonding to the substrate and represent thethickness target of the desired thin film. One or more post-processingtreatment(s) 1406 are then performed on the substrate. FIG. 15 showsexample depictions of seed layer formation using bifunctional 1200,monofunctional 1300, and oxide particle 1400 molecular self-assembly,under an embodiment.

Post processing (as it pertains to 1206, 1308, and/or 1406) in anembodiment serves as to coalesce the deposited copper containingnanoparticles and/or drive out any undesired species (e.g. OH species,NHx species, CHx species, carbonaceous species, etc.). In anotherembodiment, the post-processing can be further used to form a pure,solid, continuous copper film. The post processing (1206, 1308, and/or1406) can include thermal treatment, UV treatment, IR treatment,electron treatment, ion treatment, x-ray treatment, and/or combinationsthereof. Radiation can be chosen with the appropriate wavelength tomatch the size of the particles to maximize energy transfer and/orremoval of undesired species. The treatment may be performed in areducing (e.g. H containing, forming gas, etc.) and/or non-oxidizing,inert (e.g. Ar, He, N containing, etc.) ambient environment at, above,or below atmospheric pressure. For thermal and thermal relatedtreatments, the size of the particles generally will allow coalescenceof the nanoparticles at temperatures less than the melting point of thebulk material, nominally at less than or equal to approximately ⅔melting point of the bulk material, and more nominally at less than orequal to approximately ½ the melting point of the bulk material. Thesmaller the particle size, generally the lower the temperature requiredto achieve particle coalescence.

The thickness of the deposited layer will be largely determined by thenominal size of the nanoparticle(s). By controlling the size and sizedistribution of the nanoparticles, the thickness of the resulting filmcan be controlled with sub-nanometer (e.g. angstrom) scale resolution.The process can also be repeated to increase film thickness in a layerby layer process with compositional control analogous to gas phase ALDtype processes. Different nanoparticles can be used per layer and/orcombinations of nanoparticle types can be used per layer to adjust filmcomposition per stack and per composite stack. In such a fashion, thissame approach can be used to deposit barrier layers (e.g. with tantalumcontaining nanoparticles, tantalum nitride containing nanoparticles,tungsten nitride containing nanoparticles, titanium nitride containingnanoparticles, etc.), adhesion layers (tantalum containingnanoparticles, ruthenium containing nanoparticles, cobalt containingnanoparticles, etc.), passivation layers, other seed layers (e.g.tungsten containing nanoparticles, ruthenium containing nanoparticles,platinum containing nanoparticles, palladium containing nanoparticles,nickel containing nanoparticles, titanium containing nanoparticles,aluminum containing nanoparticles, etc.), and combinations thereof.

As described above, the molecular self-assembly of an embodiment isperformed using a MSAS, as described in the Related Applicationsreferenced above. As such, and with reference to FIG. 1 and FIG. 3, eachof the processes for forming a structure in a dielectric material,forming a MSAL on the dielectric material, forming a deposited barrierlayer on the MSAL, and forming electrically conductive material on theMSAL and/or the deposited barrier layer can be implemented in a singleor multiple processing modules. Additionally, each of the molecularself-assembly processes can be implemented in module(s) that areentirely different from, partly different from, or the same as module(s)used to implement, in whole or in part, one or both of the other of themolecular self-assembly processes. As will be understood from thedescription herein, the number and type of modules used, as well aswhether process steps are performed in the same module can depend on theparticular processes performed.

The molecular self-assembly described herein is implemented in a MSAS,as described above. Descriptions follow for several embodiments of anMSAS along with associated processes.

FIG. 16 is a substrate processing system 1600 using molecularself-assembly, under an embodiment. The substrate processing system 1600includes a pre-processing module 1601, a molecular self-assemblyprocessing module 1602, and a post-processing module 1603. Each of thepre-processing 1601, molecular self-assembly processing 1602, andpost-processing 1603 described above are implemented in a single modulethat is different from the modules used to implement the other of thepre-processing 1601, molecular self-assembly processing 1602, andpost-processing 1603, but the embodiment is not so limited. For example,any of the modules 1601, 1602, and 1603 may include functions of thepre-processing, molecular self-assembly, and/or post-processing modules.The system 1600 is not required to include at least one of each of thepreceding module types; for example, a particular process flow mayinclude only the molecular self-assembly processing module 1602 andmeans for moving a substrate into and out of the system 1600. Also,functions of all of the pre-processing, molecular self-assembly, andpost-processing modules may be embedded within a single module.

The modules 1601, 1602 and 1603 can each be implemented using apparatus(in particular, conventional commercial substrate processing apparatus)as appropriate to the types of substrate processing for which themodules 1601, 1602 and 1603 are to be used. The modules 1601, 1602, and1603 may be implemented with modification(s) and/or addition(s)depending on the particular characteristics of the molecularself-assembly. For example, when the molecular self-assembly is used toprocess semiconductor wafers, the modules 1601, 1602 and 1603 areimplemented using conventional commercial semiconductor wafer processingapparatus and methods.

Substrates enter and leave the system 1600 via a system interface 1604,also referred to as a factory interface 1604. A single substrate can beprocessed at one time in the system 1600 or multiple substrates can beprocessed at one time in a batch. The system interface 1604 includes asubstrate handler 1604 a (which can be implemented, for example, using arobot) that moves substrate(s) into and out of the system 1600. Tofacilitate moving substrates into and out of the system 1600, the systeminterface 1604 includes a substrate load station 1604 b and a substrateunloading station 1604 c (also referred to as a wafer cassette (FOUP)load station 1604 b and a wafer cassette (FOUP) unload station 1604 c,respectively).

After substrate(s) that have been processed are removed from the system1600 and placed on the substrate unload station 1604 c (for eventualmovement to another location) by the substrate handler 1604 a, newsubstrate(s) that have previously been placed on the substrate loadstation 1604 b are taken from the substrate load station 1604 b by thesubstrate handler 1604 a and moved into the system 1600 for processing.The system interface 1604 (including the substrate handler 1604 a,substrate load station 1604 b and substrate unload station 1604 c) canbe implemented using conventional apparatus and methods known to thoseskilled in the art of processing substrates. For example, when themolecular self-assembly is used to process semiconductor wafers, thesystem interface 1604 can be implemented using conventional apparatusand methods known to those skilled in the art of processingsemiconductor wafers to enable movement of a wafer and/or a cassette ofwafers into and out of the semiconductor wafer processing system. Thesystem 1600 of one or more alternative embodiments can include multiplesystem interfaces, each of which can be constructed and operate asdescribed above.

Once in the system 1600, a substrate handling system 1605 can be used tomove substrate(s) processed by the system 1600 between different modules1601-1603 of the system 1600. Like the substrate handler 1604 a of thesystem interface 1604, the substrate handling system 1605 can beimplemented, for example, using one or more robots. If the modules 1601,1602 and 1603 include both wet and dry processing modules, then thesubstrate handling system 1605 includes at least two types of apparatus:a dry substrate handler for moving substrate(s) into and out of dryprocessing modules and the system interface 1604 and out of a dryingmodule, and a wet substrate handler for moving substrate(s) into and outof wet processing modules and into a drying module. The substratehandling system 1605 can be implemented using apparatus and methodsknown to those skilled in the art of processing substrates. For example,when the molecular self-assembly is used to process semiconductorwafers, the substrate handling system 1605 can be implemented usingconventional apparatus and methods known to those skilled in the art ofprocessing semiconductor wafers to enable movement of a wafer and/or acassette of wafers between different modules of the semiconductor waferprocessing system.

Other than when substrate(s) are being moved into or out of the system1600 through the system interface 1604, the system 1600 is sealed fromthe external environment. Depending on the processing to be performed bythe system 1600, the environment within the system 1600 that is outsideof the pre-processing module 1601, molecular self-assembly processingmodule 1602, and post-processing module 1603 (for convenience, sometimesreferred to hereinafter as the “system environment”) can be maintainedat atmospheric pressure, held at a vacuum pressure, and/or pressurized(i.e., held at a pressure above atmospheric pressure). Similarly, thesystem environment can be maintained at the ambient temperature of theenvironment outside of the system 1600, or at a temperature that ishigher or lower than that ambient temperature.

Further, the gaseous composition of the system environment can becontrolled as desired. For example, the system environment can beambient air (typically, controlled to reduce contamination from theexternal environment). The system environment can also be controlled toinclude, in whole or in part, a specified gas or gases, e.g., in asystem used to process semiconductor wafers, the system environment canbe controlled to be nitrogen or an inert gas. The system environment canalso be controlled to exclude a specified gas or gases, e.g., oxygen canbe excluded from the system environment to reduce the occurrence ofoxidation of substrate(s) (or material(s) formed thereon) processed inthe system.

FIG. 17 is a substrate processing system 1700 using molecularself-assembly, under an alternative embodiment. The system 1700 includesa system interface 1704. The system interface 1704 of an embodimentincludes but is not limited to a substrate handler 1704 a, substrateload station 1704 b and a substrate unload station 1704 c for movingsubstrate(s) into and out of the system 1700. The system 1700 includes asubstrate handling system 1705 for moving substrate(s) processed by thesystem 1700 between different modules of the system 1700. Each of thesystem interface 1704, substrate handler 1704 a, substrate load station1704 b, substrate unload station 1704 c and substrate handling system1705 can be implemented and operate as described above for thecorresponding components of the system 1600 (FIG. 16). Additionally, thesystem environment described above with respect to the system 1600applies to the system environment of the system 1700.

The substrate processing system 1700 includes two pre-processing modules1701 a and 1701 b, two molecular self-assembly processing modules 1702 aand 1702 b, and two post-processing modules 1703 a and 1703 b, but isnot so limited. Alternative embodiments of system 1700 can include anynumber of each of the pre-processing modules 1701 a and 1701 b,molecular self-assembly processing modules 1702 a and 1702 b, andpost-processing modules 1703 a and 1703 b.

As described above, in substrate processing according to the molecularself-assembly, pre-processing can include both wet processing and dryprocessing. In the system 1700, the pre-processing modules 1701 a and1701 b can be dry and wet processing modules, respectively, forperforming pre-processing of substrates (e.g., pre-processing module1701 a includes a plasma (dry) surface preparation module, andpre-processing module 1701 b includes a wet clean/surface preparationmodule). Any of the wet pre-processing and dry pre-processing describedabove can be performed in the modules 1701 a and 1701 b. Thepre-processing modules 1701 a and 1701 b of various alternativeembodiments can include an pre-processing processes.

The molecular self-assembly processing modules 1702 a and 1702 b caninclude, for example, a module 1702 a for forming self-assembledmolecular material (e.g., self-assembly growth module) and a module 1702b for performing subsequent processing that functionalizes that material(e.g., functionalization module). Any of the types of molecularself-assembly and subsequent functionalization described above can beperformed in the modules 1702 a and 1702 b. The molecular self-assemblyprocessing modules 1702 a and 1702 b of various alternative embodimentscan include any self-assembly processes.

The post-processing modules 1703 a and 1703 b can include, for example,a module 1703 a for cleaning the substrate after forming material usingmolecular self-assembly (e.g., post-processing clean module) and amodule 1703 b for annealing and/or vaporizing that material (e.g.,post-processing anneal/vaporization module). Any of the types ofcleaning, annealing and vaporizing described above can be performed inthe modules 1703 a and 1703 b. The post-processing modules 1703 a and1703 b of various alternative embodiments can include anypost-processing processes.

FIG. 18 is a substrate processing system 1800 using molecularself-assembly, under another alternative embodiment. The substrateprocessing system 1800 includes one pre-processing module 1801 (e.g.,plasma (dry) surface preparation module), four molecular self-assemblyprocessing modules 1802, and one post-processing module 1803. The system1800 of alternative embodiments can include any number, type, and/orcombination of modules.

The pre-processing module 1801 of an embodiment can include a plasma(dry) surface preparation module, but is not so limited. However, any ofthe wet pre-processing and dry pre-processing described herein can beperformed in the pre-processing module 1801.

The molecular self-assembly processing modules 1802 can include, forexample, a wet clean/surface preparation module, a module for formingself-assembled molecular material (e.g., self-assembly growth module), amodule for performing subsequent processing that functionalizes thatmaterial (e.g., functionalization module), and a module for cleaning thesubstrate after forming material using molecular self-assembly (e.g.,post-processing clean module).

The post-processing module 1803 can include, for example, a module 1803for annealing and/or vaporizing that material (e.g., post-processinganneal/vaporization module). Any of the types of cleaning, annealing andvaporizing described herein can be performed in the module 1803.

The system 1800 also includes a system interface 1804, which, in turn,includes a substrate handler 1804 a, substrate load station 1804 b and asubstrate unload station 1804 c for moving substrate(s) into and out ofthe system 1800. The system 1800 includes a substrate handling system1805 for moving substrate(s) processed by the system 1800 betweendifferent modules of the system 1800. Each of the system interface 1804,substrate handler 1804 a, substrate load station 1804 b, substrateunload station 1804 c and substrate handling system 1805 can beimplemented and operate as described above for the correspondingcomponents of the system 1600 (FIG. 16). Additionally, the descriptionabove of the system environment for the system 1600 also applies to thesystem environment of the system 1800.

Like the substrate processing system 1600 described above, the substrateprocessing system 1800 includes three processing modules 1801, 1802 and1803. However, to illustrate that different types of processing stepscan be performed in the same module, the module 1802 of system 1800 isshown four times, one for each type of processing that takes place inthat module. For example, the module 1802 can be used to perform thetypes of processing that, in system 1700, take place in the fourseparate modules 1701 b, 1702 a, 1702 b and 1703 a, i.e., wetpre-processing, molecular self-assembly, functionalization ofmolecularly self-assembled material and post-processing cleaning,respectively. The system 1800 can take advantage of the capability ofcommercial substrate processing apparatus and methods to rapidly changefrom one process chemistry to another in a module to facilitate the useof a single processing module for the performance of different types ofprocess steps. In particular, in a substrate processing method includingmolecular self-assembly, multiple processing steps and multiple types ofprocessing can be performed in the same processing chamber. In general,any number and combination of processes can be performed in a singleprocessing chamber under the embodiments described herein. A spinprocessor coupling a chemistry dispense mechanism with substraterotation is an example of such a processing chamber. The chemistry canbe provided via a single dispense, a multi-port dispense, a spraydispense, and combinations thereof. Substrate rotation assists inuniform application of the process chemistries and can be used to drythe substrate.

In describing the substrate processing systems 1600, 1700 and 1800, ithas been assumed that a single wafer or a single batch of wafers isprocessed at one time. However, each of the substrate processing systems1600, 1700 and 1800 can be modified to include a multiplicity of each ofthe types of modules used to process a single wafer or single batch ofwafers, i.e., multiple versions of a substrate processing system inaccordance with the invention can operate in parallel as a singlesystem. This can be desirable to improve the throughput of substratesprocessed by a substrate processing system. This can also be desirableto add redundancy in the substrate processing system so that systemavailability can be maintained even when one or more of the modules ofthe system are rendered non-operational for a period of time (e.g., forpreventative maintenance or repair).

The molecular self-assembly systems described above are presented asexamples, and systems including other numbers of processing modules canbe used. Furthermore, types of processing modules other than thosedescribed above can be used. Manual loading and unloading ofsubstrate(s) may be used in some processing systems instead of asubstrate handler for moving substrate(s) into and out of the system.

The molecular self-assembly systems and methods described above can beused to form a masking layer on a dielectric region to facilitateforming of a capping layer on electrically conductive regions separatedby the dielectric region, as described in the Related Applications. Thecapping layer inhibits electromigration in the electrically conductiveregions (and, in some cases, enhances inhibition of diffusion ofmaterial from the electrically conductive regions). As an example, theMSAS of an embodiment forms a masking layer on one or more dielectricregions of a substrate, where the substrate includes (i.e., as part of,or having formed on and/or in) electrically conductive regions separatedby the dielectric region(s) (such a substrate is sometimes referred toherein as an “electronic device”). The electrically conductive regionscan be electrical interconnections between electrical elements (e.g.,transistors, capacitors, resistors) of the electronic device.

The masking layer can be formed selectively on the dielectric region sothat no or negligible masking layer material is formed on theelectrically conductive regions. Alternatively, the masking layer can beformed non-selectively on both the dielectric regions and theelectrically conductive regions, and masking layer material formed onthe electrically conductive regions subsequently removed.

As used herein, a “capping layer” (also sometimes referred to as a“self-aligned barrier layer”) is a layer of material formed onelectrically conductive regions of an electronic device (e.g., afterplanarization of the top of the electrically conductive regions) toinhibit electromigration in the electrically conductive regions. Inparticular, the capping layer inhibits electromigration in theelectrically conductive regions better than a dielectric barrier layerthat would otherwise be formed on the electrically conductive regions.Additionally, in some cases, a capping layer may inhibit diffusion ofmaterial from the electrically conductive regions and, in particular,may inhibit such diffusion to an extent that enables elimination, orreduction of the thickness, of a dielectric barrier layer that wouldotherwise be formed on the capping layer.

The capping layer can be formed selectively on the electricallyconductive regions so that no or negligible capping layer material isformed on the masking layer. In particular, the material(s) and/or oneor more process used to form the masking layer and/or the capping layercan be tailored to inhibit formation of capping layer material on themasking layer, thus fostering the selective formation of the cappinglayer on the electrically conductive regions. Alternatively, the cappinglayer can be formed non-selectively on both the electrically conductiveregions and the masking layer, and capping layer material formed on themasking layer subsequently removed (this can be done, for example, byremoving some or all of the masking layer and, with it, capping layermaterial formed thereon).

The MSAS of an embodiment includes forming the masking layer or cappinglayer with any degree of selectivity. As indicated above, “selective”formation of a material on a region or surface means that the materialforms on that region or surface with better coverage of the region orsurface than that with which the material forms on other region(s) orsurface(s). In any embodiment of the MSAS, masking layer material formedon electrically conductive regions or capping layer material formed onthe masking layer can be removed if deemed necessary or desirable.However, as discussed further below, removal of masking layer materialformed on electrically conductive regions or capping layer materialformed on the masking layer may not be necessary in some cases, e.g.,when negligible amounts of masking layer material are formed onelectrically conductive regions or negligible amounts of capping layermaterial are formed on the masking layer, such as may be the case whenthe masking layer is formed selectively on the dielectric regions or thecapping layer is formed selectively on electrically conductive regions,respectively.

The MSAS of an embodiment inhibits capping layer material from beingformed on the masking layer over the dielectric region (in addition tothe inhibition of formation of capping layer material on or in thedielectric region, due to the presence of the masking layer on thedielectric region). Consequently, unlike previous approaches to forminga capping layer in which a layer of electrically conductive material(e.g., a cobalt alloy, nickel alloy or tungsten) is selectivelydeposited on electrically conductive regions, the MSAS prevents theoccurrence of unacceptable current leakage between electricallyconductive regions when electrically conductive material is used to formthe capping layer. Since the MSAS inhibits formation of capping layermaterial over, on or in the dielectric region, the MSAS enables a greatdeal of flexibility in the selection of material(s) and/or one or moreprocess for forming the capping layer, without regard for theselectivity of the capping layer material for the electricallyconductive regions vis-à-vis the dielectric region (and, in someembodiments, without regard for the selectivity of the capping layermaterial for any material).

The MSAS thus enables, for example, the use of material(s) and/orprocess(es) and/or process regime(s) in the formation of the cappinglayer that would otherwise be undesirable due to a lack of sufficientselectivity. This serves to widen the material choices and/orprocess(es) and/or process regime(s) available for effecting otherdesired attributes. For example, the material and/or processes used toform the capping layer can be chosen to enhance adhesion of the cappinglayer to the electrically conductive regions (thus improving inhibitionby the capping layer of electromigration in the electrically conductiveregions). The materials and/or processes used to form the capping layercan also be chosen to produce a capping layer that does not unacceptablyor undesirably increase resistance in the electrically conductiveregions; for example, the capping layer can be formed without replacingany of the material of the electrically conductive regions with cappinglayer material having a higher resistivity. The materials and/orprocesses used to form the capping layer can also be chosen so that verylittle poisoning (undesired diffusion of constituents into and/oradverse modifications) of the electrically conductive regions occurs.Poisoning can lead to undesirable changes in electrical characteristicssuch as an increase in resistance of the electrically conductiveregions. In yet another embodiment, the materials and/or processes usedto form the capping layer can be chosen to protect the underlyingelectrically conductive regions from moisture containing environments,oxygen containing environments, oxidizing environments, and the like.

Additionally or alternatively, the materials and/or processes used toform the capping layer can be chosen to produce a capping layer that issufficiently effective in inhibiting diffusion of material used to formthe electrically conductive regions (e.g., copper) so that a dielectricbarrier layer can be eliminated from the electronic device or, at least,reduced in thickness (with attendant decrease in capacitance andassociated benefits). Further, since the masking layer inhibitsformation of capping layer material in the dielectric region, the MSASfacilitates the use of porous dielectric materials that are increasinglydeemed desirable for use in electronic devices. Additionally, the MSASenables production of a thermally stable capping layer on copper so thatthe capping layer remains continuous and defect-free (i.e., havingsufficiently few defects according to one or more criteria) undertypical operating conditions of many electronic devices.

FIG. 19 is a flow diagram for using the MSAS to form or produce 1900 acapping layer on electrically conductive regions separated by adielectric region, under an embodiment. A masking layer is formed 1901and 1902 on the electronic device so that the masking layer is formed onthe dielectric region, but not the electrically conductive regions.After formation of the masking layer, a capping layer is formed 1903,1904, 1905, and 1906 on the electronic device. Optionally, a dielectricbarrier layer can be formed 1907 on the electronic device, depending onthe properties of the capping layer, as discussed further below.

The capping layer of an embodiment is formed on the electricallyconductive regions but not on or in the dielectric region or the maskinglayer. The presence of the masking layer inhibits formation of cappinglayer material on or in the dielectric region that may otherwise haveoccurred without the masking layer. Consequently, the capping layerproduced 1900 forms capping layer material only on the electricallyconductive regions (no or negligible capping layer material is formedover, on or in a dielectric region separating electrically conductiveregions). This selective capping layer production 1900 therefore reducesor eliminates unacceptable current leakage between electricallyconductive regions of the substrate.

FIGS. 20A through 20E show cross-sectional views of an electronic device2000 undergoing formation of a capping layer 2040 on electricallyconductive regions 2010 separated by a dielectric region 2020, under themolecular self-assembly of an embodiment. The electrically conductiveregions 2010 can be interconnections between electrical elements of theelectronic device, such as, for example, transistors, capacitors andresistors. The dielectric region 2020 is illustrated with a hard masklayer 2020 a formed as a top part of the dielectric region 2020, as iscommonly the case in current electronic devices; however, the dielectricregion 2020 need not necessarily include the hard mask layer 2020 a. Asdescribed herein, the method 1900 can produce a capping layer inaccordance with various alternative embodiments not shown. Inparticular, due to imperfect selectivity or non-selectivity of theformation of the masking layer 2050, masking layer material can beformed on the electrically conductive regions 2010 that is subsequentlyremoved prior to forming the capping layer 2040. However, the formationof the masking layer 2050 may also be accomplished with greaterselectivity i) so that no masking layer material is formed on theelectrically conductive regions 2010 (in that case, the intermediatestructure shown in FIG. 20A would not occur) or ii) so that a negligibleamount of masking layer material is formed on the electricallyconductive regions 2010 that need not necessarily be removed from theelectrically conductive regions 2010 (in that case, the intermediatestructure shown in FIG. 20B would not occur and the subsequently formedstructures shown in further figures would include the negligible amountof masking layer material formed on the electrically conductive regions2010).

Generally, a masking layer 2050 is formed non-selectively on both thedielectric region 2020 and the electrically conductive regions 2010. Themasking layer material is removed from the electrically conductiveregions 2010, and capping layer material is formed selectively on theelectrically conductive regions 2010. The masking layer material isremoved from the dielectric region 2020, and a dielectric barrier layer2030 is formed over the capping layer 2040 and dielectric region 2020.

Prior to forming a masking layer in accordance with the embodimentsdescribed herein, the exposed surfaces of the electrically conductiveregions and the exposed surface of the dielectric region are preparedfor processing as described elsewhere herein. This surface preparationincludes at least one or more cleaning steps (e.g., a deionized waterrinse and/or any of a variety of other well-known surface cleaningstep(s)) to remove contaminants left from previous processing. Inparticular, a low-pH solution chemistry can be used to remove copperoxides and a high pH solution chemistry can be used to remove post CMPresidue(s).

The surface preparation can include other processing steps as well. Forexample, the exposed surfaces of the electrically conductive regionsand/or the exposed surface of the dielectric region can befunctionalized to facilitate selective formation of the masking layer.In particular, the surface of the dielectric region can befunctionalized to promote formation of the masking layer and the exposedsurfaces of the electrically conductive regions can be functionalized toinhibit formation of the masking layer. Similarly, the exposed surfacesof the electrically conductive regions and/or the exposed surface of thedielectric region can also be functionalized to facilitate selectiveformation of the capping layer. In particular, the surface of thedielectric region can be functionalized to inhibit formation of thecapping layer (though the use of a masking layer in accordance with themolecular self-assembly described herein may render this unnecessary or,at least, of greatly reduced importance) and the exposed surfaces of theelectrically conductive regions can be functionalized to promoteadhesion of the capping layer.

In general, the particular manner in which the surfaces of theelectrically conductive regions and/or the surface of the dielectricregion are functionalized depends on the nature of the materials used toform the electrically conductive regions, the dielectric region and themasking layer, and the desired properties to be produced (e.g.,passivation, promotion of material formation). For example, a dielectricregion formed of a silicon dioxide-based dielectric material can befunctionalized to produce a large number of hydroxyl groups at thesurface of the dielectric region to which a self-assembled monolayer hasan affinity for attachment, thus promoting formation of the maskinglayer on the dielectric region. Additionally, a molecule used to form amolecularly self-assembled layer can be established to include a headgroup that covalently bonds with an exposed hydroxyl group of thematerial used to form a dielectric region.

With reference to FIG. 19, a masking layer is formed 1901 and 1902 on anelectronic device so that the masking layer is formed on a dielectricregion of the electronic device, but not on the electrically conductiveregions of the electronic device that are separated by the dielectricregion. The masking layer can be formed 1901 selectively on thedielectric region or the masking layer can be formed non-selectively onboth the dielectric region and the electrically conductive regions.Selective formation of a masking layer on a dielectric regionencompasses negligible formation of masking layer material on theelectrically conductive regions, i.e., masking layer material coveragethat does not impair performance of a method according to the molecularself-assembly or the functionality of an electronic device producedusing molecular self-assembly.

Non-selective formation of a masking layer on both the dielectric regionand the electrically conductive regions encompasses formation of themasking layer with no preference for the dielectric region orelectrically conductive regions, with some degree of preference for theelectrically conductive regions, or with preference for the dielectricregion that is inadequate to result in the formation of no or negligiblemasking layer material on the electrically conductive regions. When themasking layer is formed non-selectively on the dielectric region and theelectrically conductive regions, all masking layer material formed onthe electrically conductive regions is subsequently removed 1902.Removal of all masking layer material formed on the electricallyconductive regions encompasses leaving negligible masking layer materialformed on the electrically conductive regions. Referring again to theelectronic device 2000, non-selective formation of a masking layer 2050on both the dielectric region 2020 and the electrically conductiveregions 2010 is followed by removal of all masking layer material formedon the electrically conductive regions 2010, leaving the masking layer2050 formed only on the dielectric region 2020.

In general, the masking layer can be formed using any number, type,and/or combination of materials and processes that form a masking layer.The masking layer can be formed using either wet processing (e.g.,immersion of a substrate in a chemical bath, spraying or spinning ofchemical fluid on to a substrate) or dry processing (e.g., vapordeposition). If wet processing is used, a rinsing process may be usedafterwards to clean the electronic device, which is then followed by adrying process. Additionally, if wet processing is used, vibration ofspecified amplitude and/or frequency (e.g., high frequency vibration,such as ultrasonic or megasonic vibration) can be imparted to theelectronic device during the processing to facilitate (e.g., speed up)the processing. The masking layer can be deposited or grown on thedielectric region. The masking layer can also be formed by stamping.

The masking layer of an embodiment is formed comprising an electricallyinsulative (effectively non-conductive) material, since the maskinglayer is formed in regions that, in the finished electronic device, areelectrically non-conductive. However, in embodiments in which themasking layer is completely removed from the electronic device (e.g.,FIG. 20D), the masking layer can be formed of an electrically conductiveor semiconductor material.

After formation of the masking layer, the masking layer can befunctionalized or otherwise modified (e.g., chemically, thermally and/orphoto-chemically modified) in a desired manner to produce desiredproperties (e.g., to produce a desired propensity for formation on themasking layer of material to subsequently be formed on the electronicdevice, such as a capping layer or a dielectric barrier layer, or toenable some or all of the masking layer to be removed after formation ofthe capping layer so that capping layer material formed on the maskinglayer can be removed).

The masking layer can be, for example, a molecularly self-assembledlayer, which can be formed as a monolayer (e.g. SAM) or a multilayer,and can be formed of organic and/or inorganic material. A molecularlyself-assembled layer can be produced by forming (e.g., depositing orgrowing) additional material on the surface of the dielectric region, orby chemically activating or modifying the material of the dielectricregion to produce a new distinct layer of material. The ability totailor the molecule type, head group, terminal group and/or chain lengthof a molecularly self-assembled layer as described above providesflexibility in establishing the characteristics of a masking layer,which can be used to produce desired masking layer properties, asdescribed herein. The masking layer can also be, for example, a layerformed from any class of materials known to form with controlled filmthickness, such as, for instance, multi-layer polyelectrolytes. Themasking layer can also be, for example, a layer formed on the surface ofthe dielectric region through the catalytic growth of inorganic ororganic materials. The masking layer can also be, for example, a layerformed from dendrimers, hyper-branched polymers, and/or blockco-polymers as described above. The masking layer can also be, forexample, an ionic or electrochemically-enhanced self-assembledmultilayer or monolayer.

The characteristics of a masking layer formed using the molecularself-assembly can be established to produce desired properties of themasking layer as described above. For example, the type of molecule(s)used to form a molecularly self-assembled layer can be chosen, and thecharacteristics of the molecule, such as the head group, terminal groupand/or length, can be established to produce desired properties of themolecularly self-assembled layer. The particular manner in which thecharacteristics of a masking layer are tailored include for example oneor more of the properties of the dielectric region, the necessity ordesirability of avoiding formation of masking layer material on theelectrically conductive regions, the characteristics of the materialsand/or processes used to form the capping layer, and/or thecharacteristics of the materials and/or processes used to subsequentlyform material on the masking layer, but are not so limited.

As further examples, the materials and/or processes used to form themasking layer can be selected to facilitate achievement of one or moreof the following properties: high selectivity for the dielectric region;high selectivity for a SiCOH dielectric material; high selectivity for asilicon-based hard mask layer; adheres to a dielectric barrier layer(commonly formed of a composition including silicon together with carbonand/or nitrogen, i.e., SiC_(x), SiN_(x), SiC_(x)N_(y)) or other materialto be subsequently formed on the masking layer; provides a good barrierto diffusion of the capping layer material (e.g., a cobalt alloy, suchas a cobalt-tungsten-phosphorous alloy), both during production of thecapping layer and during operation of the finished electronic device (ifthe masking layer is left as part of the finished electronic device);facilitates removal of some or all of the masking layer (and, with it,any capping layer material that may have been formed thereon), e.g.,that produce a terminal group of a molecularly self-assembled layer thatcan be cleaved from the rest of the molecularly self-assembled layer orthat produce an organic backbone of a molecularly self-assembled layerthat can be broken down and removed; produces a continuous anddefect-free layer and that, if to be left as part of the electronicdevice, remains so even when subjected to the thermal and chemicalenvironment associated with further processing to produce the electronicdevice and/or operation of the finished electronic device; enables rapid(e.g., less than about 60 seconds) production of a masking layer.

As one example, silane-based materials can be used to form a maskinglayer in one or more embodiments of the molecular self-assembly. Forexample, it is known that a silane with one or more hydrolysablesubstituents of the general formula R_(n)SiX_(4-n) (where R can be, forexample, alkyl, substituted alkyl, aryl or substituted aryl, and X canbe, for example, halo, alkoxy, aryloxy or amino) can form a SAM that canexhibit strong covalent or non-covalent attachment to particularsurfaces. Typically, SAM surface attachment is enhanced on a surfacehaving a relatively high density of acidic functionalities such ashydroxyl or hydroxysilyl groups. Silicon-based material surfaces such asSiO₂, SiOH and SiOC surfaces possess relatively high densities ofhydroxyl groups. Thus, a silane-based SAM can be expected to form withgreater adhesion to a surface of a silicon-based material (of which adielectric region is commonly formed) than to a surface of a metallicmaterial (of which electrically conductive regions are commonly formed).

Furthermore, a silane-based SAM can also be tailored to reversiblyadhere to a surface depending on the nature and substitution of a silaneprecursor material. For example, silicon-based SAM precursors with asingle hydrolysable substituent (e.g., of the general formula R¹R²R³SiX)are known to produce a SAM that can be formed on, and reversiblydetached from, a functionalized surface (e.g., a surface having arelatively high density of acidic functionalities) under specificreaction conditions. Silanization of surfaces is discussed in detail in,for example, Silanes, Surfaces and Interfaces (Chemically ModifiedSurfaces, Vol. 1), edited by Donald E. Leyden, Gordon & Breach SciencePublishers, 1986.

With reference to FIG. 19, subsequent to forming 1901 and 1902 themasking layer the molecular self-assembly of an embodiment forms 1903,1904, 1905, and 1906 a capping layer on the electronic device. Thecapping layer is formed on the electrically conductive regions, but noton or in the masking layer and/or the dielectric region. The cappinglayer can be formed 1903 selectively on the electrically conductiveregions or the capping layer can be formed non-selectively on both themasking layer and the electrically conductive regions. Selectiveformation of a capping layer on electrically conductive regionsencompasses negligible formation of capping layer material on or in themasking layer and/or dielectric region. Non-selective formation of acapping layer on both the masking layer and the electrically conductiveregions encompasses formation of the capping layer with no preferencefor the electrically conductive regions or masking layer, with somedegree of preference for the masking layer, or with preference for theelectrically conductive regions that is inadequate to result in theformation of no or negligible capping layer material on or in themasking layer and/or dielectric region.

When the capping layer is formed non-selectively on the masking layerand the electrically conductive regions, all capping layer materialformed on the masking layer is subsequently removed 1904 and 1905.Referring again to FIG. 20C, the electronic device 2000 includesselective formation of a capping layer 2040 on the electricallyconductive regions 2010; non-selective formation of a capping layer onthe masking layer and the electrically conductive regions, followed byremoval of all capping layer material formed on the masking layer isfurther described in the Related Applications.

The capping layer is generally formed using any of a number, type,and/or combination of materials and processes as appropriate to theelectronic device (e.g., that inhibits electromigration in electricallyconductive regions on which the capping layer is formed, that inhibitsdiffusion of material from electrically conductive regions on which thecapping layer is formed). The capping layer can be formed of anelectrically conductive, semiconductor or electrically insulative(effectively non-conductive) material. For example, materials (e.g.,cobalt alloys, such as an alloy of cobalt, tungsten and phosphorous oran alloy of cobalt and boron; nickel alloys, such as an alloy of nickel,molybdenum and phosphorous; tungsten; tantalum; tantalum nitride, etc.)and processes (e.g., electroless deposition; chemical vapor deposition;physical vapor deposition (sputtering); atomic layer deposition; etc.)that have previously been used to selectively deposit a capping layer onelectrically conductive regions of a semiconductor device can be used.The capping layer can be functionalized but is not so limited.

The presence of the masking layer prevents formation of capping layermaterial on or in (through diffusion) the dielectric region, thusenforcing good selectivity of the capping layer material for theelectrically conductive regions compared with the dielectric regionregardless of the selectivity otherwise associated with the material(s)and process(es) used to form the capping layer. Thus, the molecularself-assembly described herein provides increased flexibility in thematerials and processes that can be used to form the capping layer. Forexample, the molecular self-assembly enables use of materials andprocesses for depositing an electrically conductive material to form acapping layer that have previously been inadequate to form a cappinglayer without producing unacceptable current leakage betweenelectrically conductive regions, but that are effective in inhibitingelectromigration because of good adhesion to electrically conductiveregions.

Additionally, since the presence of the masking layer enables productionof a capping layer by forming additional material on an electricallyregion, there is no need to create a capping layer by chemicallymodifying a top part of the electrically conductive region. Thus, theundesirable increase in resistance in the electrically conductive regionthat is associated with creation of a capping layer in that manner isavoided using the molecular self-assembly described herein.

As described above with reference to FIGS. 19 and 20, when the cappinglayer is formed non-selectively on both the masking layer and theelectrically conductive regions, all capping layer material formed onthe masking layer is subsequently removed 1904 and 1905 so that no (ornegligible) capping layer material is present over the dielectricregion. This reduces or eliminates the possibility of current leakagebetween the electrically conductive regions when an electricallyconductive material is used to form the capping layer. Removal of thecapping layer includes removing 1905 just the capping layer materialfrom the masking layer, or removing 1904 a portion (e.g., a top part onwhich the capping layer material is formed) or all of the masking layertogether with the capping layer material formed thereon.

FIG. 21A shows a cross-section of a structure 2100 including adielectric region 2101 on which a masking layer 2102 and a capping layer2103 are formed, using the molecular self-assembly of an embodiment. Themasking layer 2102 is a self-assembled monolayer (SAM) but is not solimited. The SAM includes one or more of the following, but is not solimited: a head group 2102 a formed on the dielectric region 2101; alinking group 2102 b connected to the head group 2102 a; a terminalgroup 2102 c connected to the linking group 2102 b, on which one or moreother materials can be formed.

FIGS. 21B through 21E show additional cross-sections of the structure2100 during further processing to remove the capping layer 2103, underan embodiment. Each of FIGS. 21B through 21E illustrates a differentapproach to effect removal of a capping layer from a dielectric region.In FIG. 21B, the entire masking layer 2102 is removed from thedielectric region 2101; as a consequence of removing the masking layer2102, the capping layer 2103 is also removed from over the dielectricregion 2101.

In FIG. 21C, the head group 2102 a of the masking layer 2102 is cleaved,removing part of the head group 2102 a, all of the linking group 2102 band all of the terminal group 2102 c of the masking layer 2102, togetherwith the capping layer 2103 formed on the masking layer 2102. The partof the head group 2102 a remaining on the dielectric region 2101 isdesignated as “H” (H prime) to indicate difference from the unmodifiedhead group 2102 a of FIG. 21A.

In FIG. 21D the linking group 2102 b of the masking layer 2102 iscleaved, removing part of the linking group 2102 b and all of theterminal group 2102 c of the masking layer 2102, together with thecapping layer 2103 formed on the masking layer 2102. The part of thelinking group 2102 b remaining on the dielectric region 2101 isdesignated as “L′” (L prime) to indicate difference from the unmodifiedlinking group 2102 b of FIG. 21A.

In FIG. 21E, the terminal group 2102 c of the masking layer 2102 iscleaved, removing part of the terminal group 2102 c of the masking layer2102, together with the capping layer 2103 formed on the masking layer2102. The part of the terminal group 2102 c remaining on the dielectricregion 2101 is designated as “T′” (T prime) to indicate difference fromthe unmodified terminal group 2102 c of FIG. 21A.

Other processes (not shown) can be used to effect removal of a cappinglayer from over a dielectric region, and the molecular self-assembly ofalternative embodiments include these alternative processes. Forexample, in the structure 2100, the bond between the head group 2102 aand the linking group 2102 b can be broken, resulting in the removal ofthe linking group 2102 b and the terminal group 2102 c of the maskinglayer 2102, together with the capping layer 2103 formed on the maskinglayer 2102. Alternatively, the bond between the linking group 2102 b andthe terminal group 2102 c can be broken, resulting in the removal of theterminal group 2102 c of the masking layer 2102, together with thecapping layer 2103 formed on the masking layer 2102.

In yet another alternative process, the capping layer 2103 may beremoved from the masking layer 2102 without affecting the structure ofthe masking layer 2102, i.e., so that the terminal group 2102 c, thelinking group 2102 b and the head group 2102 a are not cleaved and thebonds there between are not broken. Additionally, two or more of theabove-described processes can be combined; this may for example increasethe likelihood that the capping layer 2102 is adequately removed fromover the dielectric region 2101. Furthermore, in any of the processesdescribed above in which at least part of the masking layer 2102 remainson the dielectric region 2101 after removal of the capping layer 2103,the exposed part of the masking layer 2102 can be functionalized toproduce desired characteristic(s) (this is true for any type of maskinglayer in accordance with the molecular self-assembly, not only themasking layer 2102).

Referring again to FIG. 19, when capping layer material is removed 1904and 1905 from the masking layer, the removal 1904 and 1905 under themolecular self-assembly of an embodiment includes subsequent removal1906 of all of the masking layer or modification of the masking layer(i.e., removing some and/or functionalizing). Removing 1906 all of, ormodifying, the masking layer may be used to produce a surface (i.e., anexposed surface of the masking layer or the dielectric region) havingparticular characteristics (e.g., good propensity for adhesion to adielectric barrier layer subsequently to be formed on the maskinglayer). When first removing the capping layer, then removing ormodifying the masking layer, the process of an embodiment removes someor all of the masking layer (and/or to functionalize the masking layer)after removing the capping layer (rather than together with removal ofthe capping layer) for one or more of a variety of reasons. Any of avariety of processes can be used to remove masking layer material fromthe dielectric region. Similarly, any of a variety of processes can beused to functionalize a masking layer. The particular process orprocesses used in an embodiment to remove masking layer material fromthe dielectric region and/or to functionalize the masking layer candepend, in particular, on the characteristics of the masking layermaterial, and may also depend on the material used to form thedielectric region.

A dielectric barrier layer can also be formed 1907 on the electronicdevice or not, depending on the properties of the capping layer. FIG.20E shows formation of a dielectric barrier layer 2030 on the electronicdevice 2000. If a dielectric barrier layer is formed on the electronicdevice, such formation can be accomplished using any type, number,and/or combination of materials and/or processes.

When the capping layer is formed of a material that provides goodinhibition of diffusion of the electrically conductive material intoadjacent material of the electronic device while still providing otherrequired properties of the capping layer, it is possible to eliminatethe dielectric barrier layer from the electronic device or, at least,reduce the thickness of the dielectric barrier layer. The molecularself-assembly of an embodiment forms a capping layer so that diffusionof material from the electrically conductive regions into adjacentregions is inhibited with sufficient effectiveness that the dielectricbarrier layer can be formed with a smaller thickness than would be thecase if the capping layer was not present.

The molecular self-assembly of other embodiments forms a capping layerso that diffusion of material from the electrically conductive regionsinto adjacent regions is inhibited with sufficient effectiveness that adielectric barrier layer need not be formed. Eliminating the dielectricbarrier layer or reducing the thickness of the dielectric barrier layerreduces capacitance, which can decrease the power consumption and/orincrease speed of operation of the electronic device. By using a maskinglayer on the dielectric region to minimize or eliminate selectivity asan important consideration in choosing materials and/or processes forforming the capping layer, the molecular self-assembly enables formationof a capping layer that provides adequate inhibition of electromigrationand a good barrier to diffusion of electrically conductive material.This enables elimination or reduction in thickness of a conventionaldielectric barrier layer. The capping layer can also be optimized toresist against any deleterious effects associated with subsequentexposure to moisture containing environments, oxygen containingenvironments, oxidizing environments, and the like.

The molecular self-assembly described above can be used in theprocessing of a substrate comprising any type of material. For example,the molecularly self-assembled material can be formed on materialpreviously formed on a substrate and can be formed on material(substrate or other material) that has been functionalized to havedesired properties, such as desired adhesion characteristics. Inparticular, the molecular self-assembly can be used in processingsemiconductor substrates as in the manufacture of components for use inthe electronics industry. The molecular self-assembly can also be usedin processing substrates like glass, silicon, and/or plastic for use inthe production of flat panel displays, for example. The molecularself-assembly can be used in the processing of any type of semiconductorsubstrate, including but not limited to silicon substrates,silicon-on-insulator substrates, silicon carbide substrates, strainedsilicon substrates, silicon germanium substrates, and gallium arsenidesubstrates.

The molecular self-assembly can include a substrate of any size. Forexample, the molecular self-assembly can be used in the processing ofsmall semiconductor substrates having areas of less than one square inchup to twelve (12) inch (300 millimeter (mm)) or larger semiconductorsubstrates used in the production of many electronic components. Ingeneral, there is no limit to the size of substrates that can beprocessed. For example, the molecular self-assembly can be used toprocess each succeeding larger generation of semiconductor substratesused to produce electronic components. The molecular self-assembly canalso be used to process the relatively large substrates that are used inthe production of flat panel displays. Such substrates includerectangular substrates on the order of approximately one square meter,but larger substrates can be used. The molecular self-assembly can alsobe scaled for use in roll-to-roll processing applications for flexiblesubstrates having a fixed width, but (theoretically) unlimited length (amanner of substrate processing that can be particularly useful in theproduction of flat panel displays); for example, such substrate rollscan be hundreds of feet long.

The molecular self-assembly can be used in processing substrates of anyshape, e.g., circular, rectangular (including square), etc. For example,and as described above, the molecular self-assembly can be used in theprocessing of semiconductor substrates used in the production ofelectronic components (e.g., circular substrates), as well as in theprocessing of substrates used in the production of flat panel displays(e.g., rectangular substrates).

The molecular self-assembly can be used in the processing of a singlesubstrate or multiple substrates (e.g., batch processing). For example,in wet semiconductor processing, a single substrate can be processed ora batch of, for example, 13, 25 or 50 substrates can be processed at asingle time. In dry semiconductor processing and flat panel displayproduction, typically, a single substrate is processed at one time.

The molecular self-assembly described herein can include wet processingand/or dry processing. In wet processing, a substrate is processed usinga fluid. For example, the substrate can be immersed, in whole or inpart, in a fluid having specified characteristics (e.g., a specifiedchemical composition). Also, for example, a fluid can be sprayed on tothe substrate in a specified manner. Wet processing for use with themolecular self-assembly of an embodiment can make use of any of avariety of chemical constituents, as appropriate for the desiredprocessing.

In dry processing (e.g., physical vapor deposition, chemical vapordeposition, plasma-enhanced chemical vapor deposition, and atomic layerdeposition), a plasma or gas is used to produce a desired interactionwith a substrate that processes a substrate surface in a specified way.Dry processing for use with the molecular self-assembly can make use ofinert or reactive gases, as appropriate for the desired processing.

Any of a variety of chemical constituents or other reactants(collectively referred to herein as constituents or chemicalconstituents) can be used by a molecular self-assembly system of anembodiment to effect molecular self-assembly and related processes. Theconstituents can be in the liquid phase, gaseous phase, and/or somecombination of the liquid and gaseous phases (including, for example,the super-critical fluid phase). The constituents used and theirconcentrations, as well as the mixture of constituents, will depend onthe particular process step(s) to be performed. The chemical deliverysystem can enable precise control of the molar concentrations,temperature, flow rate and pressure of chemical constituents asappropriate to the process. The chemical delivery system can alsoprovide appropriate filtration and control of contamination.

The molecular self assembly of an embodiment includes a methodcomprising receiving a substrate. The substrate includes at least onedielectric material. A molecularly self-assembled layer is formed on anexposed surface of the dielectric material, the molecularlyself-assembled layer comprising at least one material having at leastone of a molecular characteristic and a molecular type that includes oneor more of a molecular type of a head group of molecules of thematerial, a molecular characteristic of a head group of molecules of thematerial, a molecular type of a terminal group of molecules of thematerial, a molecular characteristic of a terminal group of molecules ofthe material, a molecular type of a linking group of molecules of thematerial, and a molecular characteristic of a linking group of moleculesof the material, wherein the at least one of the molecularcharacteristic and molecular type are selected according to at least onepre-specified property of the molecularly self-assembled layer.

The method of an embodiment comprises preparing the exposed surface ofthe dielectric material, wherein preparing includes one or more offunctionalization, cleaning, etching, rinsing, drying, vaporization,annealing, curing, thermal treatment, UV treatment, IR treatment,electron treatment, ion treatment, and x-ray treatment.

The method of an embodiment comprises post-processing the molecularlyself-assembled layer, wherein the post-processing includes one or moreof functionalization, cleaning, etching, rinsing, drying, vaporization,annealing, curing, thermal treatment, UV treatment, IR treatment,electron treatment, ion treatment, and x-ray treatment.

The at least one pre-specified property of the molecularlyself-assembled layer of an embodiment includes one or more of poresealing properties, adhesion properties, diffusion barrier properties,passivation properties, and selectivity.

The at least one pre-specified property of an embodiment is specifiedaccording to at least one of an application of the molecularlyself-assembled layer, a type of the dielectric material, and a type ofthe material to be subsequently formed on the molecularly self-assembledlayer.

The at least one pre-specified property of an embodiment includes aplurality of properties, further comprising assigning degrees ofimportance to each of the plurality of properties.

The method of an embodiment comprises one or more of cross-linking,polymerizing, and oligomerizing molecules of the molecularlyself-assembled layer.

Forming the molecularly self-assembled layer of an embodiment comprisesjoining complementary materials in nano-molecular action usingcoordinated action of independent molecules under distributed control.

The dielectric material of an embodiment is a porous dielectricmaterial, wherein the at least one of a molecular characteristic and amolecular type causes the molecularly self-assembled layer to seal amajority of pores of the exposed surface of the dielectric material

The molecular type of an embodiment is an organic molecule and themolecular characteristic includes at least one of a size and a length ofone or more of a terminal group and a linking group.

The at least one of the molecular characteristic and the molecular typeof an embodiment comprise a carbon chain including at least one of alinking group and a terminal group, wherein a length of at least one ofthe linking group and the terminal group is long enough relative to asize of the pores of the exposed surface so as to seal the pores.

Sealing of the majority of pores of an embodiment prevents diffusion ofat least one of reactants, reagents, precursors, and carrier gases fromsubsequent depositions into the porous dielectric material.

The method of an embodiment comprises etching at least one structure inthe dielectric material.

The at least one structure of an embodiment includes one or more of atleast one via and at least one trench.

The method of an embodiment comprises forming at least one depositedbarrier layer on the molecularly self-assembled layer, wherein thedeposited barrier layer prevents diffusion of other materials into thedielectric material.

The method of an embodiment comprises forming at least one conductivelayer on the at least one deposited barrier layer, wherein the at leastone conductive layer comprises at least one electrically conductivematerial.

The at least one conductive layer of an embodiment includes a seedlayer.

The method of an embodiment comprises filling the at least one structurewith the at least one electrically conductive material.

The at least one electrically conductive material of an embodimentincludes one or more of copper, ruthenium, tungsten, and aluminum.

The molecularly self-assembled layer of an embodiment forms a maskinglayer on the dielectric material.

The method of an embodiment comprises cleaning the substrate, whereinthe cleaning includes removing contamination from an electricallyconductive material at a bottom portion of the at least one structure,wherein a portion of the contamination is captured in the masking layer.

The masking layer of an embodiment protects the dielectric materialduring the cleaning.

The cleaning of an embodiment generates an anchor area at the bottomportion of the at least one structure by removing a portion of theelectrically conductive material at the bottom portion of the at leastone structure.

The method of an embodiment comprises forming a structural anchor in theanchor area by filling the anchor area with material of at least one ofbarrier layer deposition, seed layer deposition, and bulk copper fillduring at least one of the barrier layer deposition, the seed layerdeposition, and the bulk copper fill.

The electrically conductive material of an embodiment is a metal,wherein the contamination includes at least one of organiccontamination, metallic contamination, and metal oxide contamination.

The method of an embodiment comprises removing the masking layer from atleast a portion of the dielectric material, wherein removing the maskinglayer includes removing the contamination.

The method of an embodiment comprises forming a capping layer over anexposed surface of the electrically conductive material at the bottomportion of the at least one structure.

Forming of the metal alloy capping layer of an embodiment includesdelivering and effecting a plating chemistry for electroless plating ofthe capping layer, wherein the capping layer is a metal alloy cappinglayer.

The method of an embodiment comprises removing excess material of thecapping layer.

The method of an embodiment comprises removing the masking layer from atleast a portion of the dielectric material, wherein removing the maskinglayer includes removing at least one of the contamination, material ofthe capping layer, and the excess material of the capping layer.

The method of an embodiment comprises preparing the exposed surface,wherein the preparing further includes preparing an exposed surface ofan electrically conductive material at a bottom portion of at least onestructure of the dielectric material.

The method of an embodiment comprises functionalizing at least oneterminal group of the molecularly self-assembled layer by modifying atleast one characteristic of the terminal group so as to generate apre-specified interaction with at least one other material formed on themolecularly self-assembled layer.

The method of an embodiment comprises selecting the at least one of themolecular characteristic and the molecular type to provide apre-specified force of adhesion between the molecularly self-assembledlayer and the dielectric material.

The adhesion of an embodiment is produced by covalent bonding betweenmolecules of at least one material, wherein the at least one materialincludes material of the molecularly self-assembled layer and thedielectric material.

The adhesion of an embodiment includes covalent bonding between siliconand one or more of oxygen, carbon, and nitrogen.

The at least one of the molecular characteristic and the molecular typeof an embodiment includes a pre-specified head group for molecules ofthe material.

The method of an embodiment comprises selecting the at least one of themolecular characteristic and the molecular type to provide apre-specified force of adhesion between the molecularly self-assembledlayer and at least one material formed on the molecularly self-assembledlayer.

The at least one of the molecular characteristic and the molecular typeof an embodiment includes a pre-specified terminal group for moleculesof the material.

The dielectric material of an embodiment comprises a semiconductorsubstrate.

The molecularly self-assembled layer of an embodiment is a monolayer.

The molecularly self-assembled layer of an embodiment is a multilayer.

The molecularly self-assembled layer of an embodiment comprises anorganic material.

The molecularly self-assembled layer of an embodiment comprises aninorganic material.

The molecularly self-assembled layer of an embodiment comprises thiolmolecules.

The molecularly self-assembled layer of an embodiment comprisessilicon-based molecules.

The molecularly self assembled layer of an embodiment comprises at leastone of a cluster of atoms, a cluster of functionalized atoms,nanoparticles, and functionalized nanoparticles.

The molecularly self-assembled layer of an embodiment comprisesmolecules including organosilanes.

The molecularly self-assembled layer of an embodiment comprises one ormore of dendrimers, hyper-branched polymers, polymer brushes, and blockco-polymers.

The dielectric constant of the dielectric material of an embodiment isless than or equal to approximately 2.5.

The size of the pores of the dielectric material of an embodiment isapproximately in a range of ten (10) angstroms to fifty (50) angstroms.

The porosity of the dielectric material of an embodiment is equal to orless than approximately fifty percent (50%).

The methods, processes, and systems described above for molecularself-assembly can be used to produce or manufacture semiconductordevices.

Aspects of the molecular self-assembly systems and methods describedherein may be implemented as functionality programmed into any of avariety of circuitry, including programmable logic devices (PLDs), suchas field programmable gate arrays (FPGAs), programmable array logic(PAL) devices, electrically programmable logic and memory devices andstandard cell-based devices, as well as application specific integratedcircuits (ASICs). Some other possibilities for implementing aspects ofthe molecular self-assembly systems and methods include:microcontrollers with memory (such as electronically erasableprogrammable read only memory (EEPROM)), embedded microprocessors,firmware, software, etc. Furthermore, aspects of the molecularself-assembly systems and methods may be embodied in microprocessorshaving software-based circuit emulation, discrete logic (sequential andcombinatorial), custom devices, fuzzy (neural) logic, quantum devices,and hybrids of any of the above device types. Of course the underlyingdevice technologies may be provided in a variety of component types,e.g., metal-oxide semiconductor field-effect transistor (MOSFET)technologies like complementary metal-oxide semiconductor (CMOS),bipolar technologies like emitter-coupled logic (ECL), polymertechnologies (e.g., silicon-conjugated polymer and metal-conjugatedpolymer-metal structures), mixed analog and digital, etc.

It should be noted that the various components disclosed herein may bedescribed and expressed (or represented) as data and/or instructionsembodied in various computer-readable media. Computer-readable media inwhich such data and/or instructions may be embodied include, but are notlimited to, non-volatile storage media in various forms (e.g., optical,magnetic or semiconductor storage media) and carrier waves that may beused to transfer such formatted data and/or instructions throughwireless, optical, or wired signaling media or any combination thereof.Examples of transfers of such data and/or instructions by carrier wavesinclude, but are not limited to, transfers (uploads, downloads, e-mail,etc.) over the Internet and/or other computer networks via one or moredata transfer protocols (e.g., HTTP, FTP, SMTP, etc.). When receivedwithin a computer system via one or more computer-readable media, suchdata and/or instruction-based expressions of the above-describedcomponents may be processed by a processing entity (e.g., one or moreprocessors) within the computer system in conjunction with execution ofone or more other computer programs.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense as opposed to anexclusive or exhaustive sense; that is to say, in a sense of “including,but not limited to.” Words using the singular or plural number alsoinclude the plural or singular number respectively. Additionally, thewords “herein,” “hereunder,” “above,” “below,” and words of similarimport refer to this application as a whole and not to any particularportions of this application. When the word “or” is used in reference toa list of two or more items, that word covers all of the followinginterpretations of the word: any of the items in the list, all of theitems in the list and any combination of the items in the list.

The above description of illustrated embodiments of the molecularself-assembly systems and methods is not intended to be exhaustive or tolimit the molecular self-assembly systems and methods to the preciseform disclosed. While specific embodiments of, and examples for, themolecular self-assembly systems and methods are described herein forillustrative purposes, various equivalent modifications are possiblewithin the scope of the molecular self-assembly systems and methods, asthose skilled in the relevant art will recognize. The teachings of themolecular self-assembly systems and methods provided herein can beapplied to other processing systems and methods, not only for thesystems and methods described above.

The elements and acts of the various embodiments described above can becombined to provide further embodiments. These and other changes can bemade to the molecular self-assembly systems and methods in light of theabove detailed description.

In general, in the following claims, the terms used should not beconstrued to limit the molecular self-assembly systems and methods tothe specific embodiments disclosed in the specification and the claims,but should be construed to include all processing systems that operateunder the claims. Accordingly, the molecular self-assembly systems andmethods are not limited by the disclosure, but instead the scope of themolecular self-assembly systems and methods is to be determined entirelyby the claims.

While certain aspects of the molecular self-assembly systems and methodsare presented below in certain claim forms, the inventors contemplatethe various aspects of the molecular self-assembly systems and methodsin any number of claim forms. Accordingly, the inventors reserve theright to add additional claims after filing the application to pursuesuch additional claim forms for other aspects of the molecularself-assembly systems and methods.

What is claimed is:
 1. A method comprising: receiving a substrate, thesubstrate comprising a porous dielectric material forming a surface;forming a molecularly self-assembled layer on the surface of the porousdielectric material, the molecularly self-assembled layer comprisingmolecules having chain lengths and head groups selected to seal pores onthe surface of the porous dielectric material; processing themolecularly self-assembled layer using one of cleaning, reactiveetching, vaporization, annealing, or curing the substrate; and forming abarrier layer over the molecularly self-assembled layer after processingthe molecularly self-assembled layer, wherein the molecularlyself-assembled layer prevents materials of the barrier layer fromcontacting the porous dielectric material of the substrate.
 2. Themethod of claim 1, wherein a volumetric pore fraction of the porousdielectric material is less than or equal to 50%.
 3. The method of claim1, wherein the chain lengths are less than or equal to 25 Angstroms. 4.The method of claim 1, wherein the chain lengths are less than or equalto 10 Angstroms.
 5. The method of claim 1, wherein the molecules of themolecularly self-assembled layer are cross-linked.
 6. The method ofclaim 1, wherein the head groups are covalently bound to hydroxyl groupsof the dielectric material.
 7. The method of claim 1, wherein themolecules further comprising terminal groups represented by NR_(x),wherein R_(x) is at least one of hydrogen atoms or one or more organicgroups.
 8. The method of claim 1, wherein the barrier layer comprises atitanium-based material, a tantalum based material, a ruthenium basedmaterial, or a tungsten-based material.
 9. The method of claim 1,wherein the barrier layer is formed using atomic layer deposition andwherein the molecularly self-assembled layer is configured to bind aprecursor used to form the barrier layer and to prevent the precursorfrom contacting the surface of the porous dielectric.
 10. The method ofclaim 9, wherein the barrier layer comprises one of tantalum, tantalumnitride, tantalum carbon nitride, tungsten nitride, tungsten carbonnitride, or ruthenium.
 11. The method of claim 9, wherein the precursorused to form the barrier layer comprises one of TDMAT, TDEAT, PDMAT,TBTDET, TBTEMT, WF6, ruthenocene, or a derivative of ruthenocene. 12.The method of claim 1, wherein the molecules of the molecularlyself-assembled layer comprise one or more thiols represented by R—SH,wherein R is one of alkyl, aryl, heteroaryl, fluorinated alkyl,fluorinated aryl, fluorinated heteroaryl, functionalized alkyl,functionalized aryl, or functionalized heteroaryl.
 13. The method ofclaim 12, wherein the one or more thiols are functionalized with metals.14. The method of claim 1, wherein the molecules of the molecularlyself-assembled layer comprise one or more organosilanesR_(n)—Si—X_(4-n), wherein n is 1, 2, or 3, wherein R is one of hydrogen,an alkyl, an alkenyl, an alkynyl, an aryl, a fluoroalkyl, a heteroaryl,a fluoroheteroaryl, an alcohol, a thiol, an amine, an amide, an imine, acarboxylic acid, a thiocarboxylic acid, a thiocarbamate, a ester, anether, a sulfide, or a nitrile, X is a halide, a carboxylate, an amine,an alkoxide, a sulfide, a heteroaryl, or a fluororoaryl.
 15. The methodof claim 14, further comprises subjecting the molecules of themolecularly self-assembled layer to hydrolysis.
 16. The method of claim1, further comprising cleaning the surface of the porous dielectricmaterial prior to forming the molecularly self-assembled layer on thesurface of the porous dielectric material.
 17. The method of claim 16,wherein cleaning the surface of the porous dielectric material comprisesdelivering a cleaning solution to the surface of the porous dielectricmaterial.
 18. The method of claim 1, wherein the molecularlyself-assembled layer is formed on selected portions of the surface ofthe porous dielectric material while remaining portions of the surfaceare free from the molecularly self-assembled layer.
 19. A methodcomprising: receiving a substrate, the substrate comprising a porousdielectric material forming a surface, the surface comprising hydroxylgroups; forming a molecularly self-assembled layer on the surface of theporous dielectric material, the molecularly self-assembled layercomprising molecules having chain lengths and head groups selected toseal pores on the surface of the porous dielectric material, the chainlengths being less than or equal to 10 Angstroms, the head groupscovalently binding to the hydroxyl groups on the surface of thedielectric material. processing the molecularly self-assembled layerusing one of cleaning, reactive etching, vaporization, annealing, orcuring the substrate; and forming a barrier layer over the molecularlyself-assembled layer after processing the molecularly self-assembledlayer, wherein the molecularly self-assembled layer prevents materialsof the barrier layer from contacting the porous dielectric material ofthe substrate, and wherein the barrier layer comprises one of tantalum,tantalum nitride, tantalum carbon nitride, tungsten nitride, tungstencarbon nitride, or ruthenium.
 20. A semiconductor substrate comprising:a porous dielectric material comprising a surface; a molecularlyself-assembled layer disposed on the surface of the porous dielectricmaterial, wherein the molecularly self-assembled layer comprisingmolecules having chain lengths and head groups selected to seal pores onthe surface of the porous dielectric material; and a barrier layerdisposed over the molecularly self-assembled layer, wherein themolecularly self-assembled layer prevents materials of the barrier layerfrom contacting the porous dielectric material of the substrate.